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Sample records for voltage dividers temperature

  1. 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.

  2. Enhanced Model of Nonlinear Spiral High Voltage Divider

    Directory of Open Access Journals (Sweden)

    V. Panko

    2015-04-01

    Full Text Available This paper deals with the enhanced accurate DC and RF model of nonlinear spiral polysilicon voltage divider. The high resistance polysilicon divider is a sensing part of the high voltage start-up MOSFET transistor that can operate up to 700 V. This paper presents the structure of a proposed model, implemented voltage, frequency and temperature dependency, and scalability. A special attention is paid to the ability of the created model to cover the mismatch and influence of a variation of process parameters on the device characteristics. Finally, the comparison of measured data vs. simulation is presented in order to confirm the model validity and a typical application is demonstrated.

  3. Next generation KATRIN high precision voltage divider for voltages up to 65kV

    CERN Document Server

    Bauer, S; Hochschulz, F; Ortjohann, H -W; Rosendahl, S; Thümmler, T; Schmidt, M; Weinheimer, C

    2013-01-01

    The KATRIN (KArlsruhe TRItium Neutrino) experiment aims to determine the mass of the electron antineutrino with a sensitivity of 200meV by precisely measuring the electron spectrum of the tritium beta decay. This will be done by the use of a retarding spectrometer of the MAC-E-Filter type. To achieve the desired sensitivity the stability of the retarding potential of -18.6kV has to be monitored with a precision of 3ppm over at least two months. Since this is not feasible with commercial devices, two ppm-class high voltage dividers were developed, following the concept of the standard divider for DC voltages of up to 100kV of the Physikalisch-Technische Bundesanstalt (PTB). In order to reach such high accuracies different effects have to be considered. The two most important ones are the temperature dependence of resistance and leakage currents, caused by insulators or corona discharges. For the second divider improvements were made concerning the high-precision resistors and the thermal design of the divider....

  4. Binary Versus Decade Inductive Voltage Divider Comparison and Error Decomposition

    Science.gov (United States)

    1995-08-01

    1995 IEEE Authorized licensed use limited to: US Naval Academy. Downloaded on January 30, 2009 at 11:28 from IEEE Xplore . Restrictions apply...Downloaded on January 30, 2009 at 11:28 from IEEE Xplore . Restrictions apply. 906 s, A U U U U U l f U U J s, sa I IEEE TRANSACTIONS ON...30, 2009 at 11:28 from IEEE Xplore . Restrictions apply. AVRAMOV-ZAMUROVIC et al.: BINARY VERSUS DECADE INDUCTIVE VOLTAGE DIVIDER COMPARISON AND ERROR

  5. Program-Controlled High Voltage Module in Active Voltage Dividers(AVD) for MPGD

    CERN Document Server

    Ginting, Muhammad Fadhil

    2016-01-01

    Micro Pattern Gas Detectors (MPGD) applications are rapidly developing and became an important part of upgrades for the LHC detectors. RD51/CERN have worked on Active Voltage Divider (AVD) technology for multistage MPGDs, One of the next developments for the AVD is to design and integrate high voltage module in a single box. The Program-Controlled High Voltage Module, part of one AIDA2020 project, has been successfully designed and developed, and can be integrated in AVD design.

  6. HIGH VOLTAGE SMALL – SIZED ALTERNATIVE CURRENT RESISTIVE DIVIDERS FROM MICROWIRE

    Directory of Open Access Journals (Sweden)

    Berzan V.P.

    2011-04-01

    Full Text Available The paper discusses the design parameters and characteristics of the new product, the resistive voltage divider produced from microwire for measuring high-voltage alternating current. Resistive dividers are designed for use in AC circuits and power-frequency electric traction network traffic. Dividers have smaller mass-dimensional size compared with the measuring voltage transformers and higher accuracy class 0.2 at a fixed frequency.

  7. A novel water resistor divider with a coaxial low-voltage arm.

    Science.gov (United States)

    Jia, Wei; Chen, Weiqing; Mao, Congguang; Zeng, Jiangtao

    2010-03-01

    A new style high voltage resistor divider made of saline solution has been constructed and tested. A coaxial construction is used on the low-voltage arm, as the signal extraction electrode, which can increase the attenuation ratio of the divider. The time response of divider limited by the stray parameter also can be improved. Comparing the results of calibrated experiment with the commonly used equal size copper sulfate dividers, the new probe has nearly five times increase in the attenuation ratio. The time response of the new style divider in the dimension of 30 mm in diameter and 400 mm in length can reach to 1 ns.

  8. Spectroscopic measurements with a silicon drift detector having a continuous implanted drift cathode-voltage divider

    CERN Document Server

    Bonvicini, V; D'Acunto, L; Franck, D; Gregorio, A; Pihet, P; Rashevsky, A; Vacchi, A; Vinogradov, L I; Zampa, N

    2000-01-01

    A silicon drift detector (SDD) prototype where the drift electrode also plays the role of a high-voltage divider has been realised and characterised for spectroscopic applications at near-room temperatures. Among the advantages of this design, is the absence of metal on the sensitive surface which makes this detector interesting for soft X-rays. The detector prototype has a large sensitive area (2x130 mm sup 2) and the charge is collected by two anodes (butterfly-like detector). The energy resolution of a such a detector has been investigated at near-room temperatures using a commercial, hybrid, low-noise charge-sensitive preamplifier. The results obtained for the X-ray lines from sup 5 sup 5 Fe and sup 2 sup 4 sup 1 Am are presented.

  9. 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.

  10. An Internal ALD-Based High Voltage Divider and Signal Circuit for MCP-based Photodetectors

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Bernhard W.; Elagin, Andrey; Elam, Jeffrey W.; Frisch, Henry J.; Genat, Jean-Francois; Gregar, Joseph S.; Mane, Anil U.; Minot, Michael J.; Northrup, Richard; Obaid, Razib; Oberla, Eric; Alexander, Vostrikov; Wetstein, Matthew

    2015-04-21

    We describe a pin-less design for the high voltage (HV) resistive divider of the all-glass LAPPD (TM) 8 in,square thin photodetector module. The divider, which distributes high voltage applied to the photocathode to the two micro-channel plates (MCPs) that constitute the amplification stage, is comprised of the two MCPs and three glass mechanical spacers, each of which is coated with a resistive layer using atomic layer deposition (ALD). The three glass grid spacers and the two MCPs form a continuous resistive path between cathode and anode, with the voltages across the MCPs and the spacers determined by the resistance of each. High voltage is applied on an external tab on the top glass window that connects to the photocathode through the metal seal. The DC ground is supplied by microstrips on the bottom glass plate that form the high-bandwidth anode. The microstrips exit the package through the glass-frit seal of the anode base-plate and the package sidewall. The divider is thus completely internal, with no HV pins penetrating the low-profile flat glass package. Measurements of the performance of the divider are presented for the 8 in.-square MCP and spacer package in a custom test fixture and for an assembled externally pumped LAPPD (TM) prototype with an aluminum photocathode. (C) 2015 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Divani, Nazila, E-mail: n-divani@birjand.ac.ir; Firoozabadi, Mohammad M. [Dep. Of Physics, Faculty of Science, University of Birjand, Birjand (Iran, Islamic Republic of); Bayat, Esmail [Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran (Iran, Islamic Republic of)

    2014-11-24

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

  12. ELABORATION AND TESTING OF SOFTWARE FOR SIGNAL PROCESSING OF RESISTIVE HIGH VOLTAGE DIVIDER

    Directory of Open Access Journals (Sweden)

    Sit М.

    2009-12-01

    Full Text Available Mathematical tools and the software for input in the computer of signals of a resistive divider of a high voltage of the industrial frequency, providing a split-hair accuracy of measurement of parameters of the basic and harmonics which are divisible to the basic is developed.

  13. KCNE1 divides the voltage sensor movement in KCNQ1/KCNE1 channels into two steps

    Science.gov (United States)

    Barro-Soria, Rene; Rebolledo, Santiago; Liin, Sara I.; Perez, Marta E.; Sampson, Kevin J.; Kass, Robert S.; Larsson, H. Peter

    2014-04-01

    The functional properties of KCNQ1 channels are highly dependent on associated KCNE-β subunits. Mutations in KCNQ1 or KCNE subunits can cause congenital channelopathies, such as deafness, cardiac arrhythmias and epilepsy. The mechanism by which KCNE1-β subunits slow the kinetics of KCNQ1 channels is a matter of current controversy. Here we show that KCNQ1/KCNE1 channel activation occurs in two steps: first, mutually independent voltage sensor movements in the four KCNQ1 subunits generate the main gating charge movement and underlie the initial delay in the activation time course of KCNQ1/KCNE1 currents. Second, a slower and concerted conformational change of all four voltage sensors and the gate, which opens the KCNQ1/KCNE1 channel. Our data show that KCNE1 divides the voltage sensor movement into two steps with widely different voltage dependences and kinetics. The two voltage sensor steps in KCNQ1/KCNE1 channels can be pharmacologically isolated and further separated by a disease-causing mutation.

  14. Voltage, Temperature, Frequency Margin Test Report

    DEFF Research Database (Denmark)

    Denver, Troelz

    1999-01-01

    The purpose of the tests is to establish the camera functionality when it is exposed to an extreme environment for prolonged periods, thus simulating the end of life performance. This environment covers temperature, input clock frequency and supply voltage variation......The purpose of the tests is to establish the camera functionality when it is exposed to an extreme environment for prolonged periods, thus simulating the end of life performance. This environment covers temperature, input clock frequency and supply voltage variation...

  15. Fault Analysis of DC Voltage Dividers in Xiangjiaba--Shanghai ±800 kV UHVDC Project

    Institute of Scientific and Technical Information of China (English)

    LI Fengqi; SHE Zhengqiu; LOU Dianqiang; Rajendra Iyer; Urban Astrom

    2012-01-01

    Transient DC voltage measurement error has been observed several times ever since Xiangjiaba--Shanghai ±800 kV UHVDC project started its commercial operation. The measurement error causes considerable disturbances to the AC networks. By analyzing the time frequency record, simulating faults at different positions of the divider, and testing the gas in voltage dividers, the fault is located and then is proved to be some partial discharges inside DC voltage dividers. The reason of the internal flashes and the solution to the problem is also discussed in this paper. The conclusion is that instead of N2 , SF6 should be used for the internal insulation of high voltage DC voltage dividers.

  16. Analysis of the match problem of a capacitive voltage divider with a long measurement cable

    Science.gov (United States)

    Yu, Bin-Xiong; Li, Rui; Su, Jian-Cang; Zhao, Liang; Zhang, Yu; Zheng, Lei; Zeng, Bo; Cheng, Jie; Gao, Peng-Cheng; Qiu, Xu-Dong; Xu, Xu-dong

    2017-09-01

    Research is carried out on the basis of the traditional two-end matched circuit of a capacitive voltage divider with a long measurement cable. Transmission progress in the circuit is analyzed theoretically. A match condition of the circuit is acquired, which requires that the circuit satisfies two conditions: (1) the measurement error should be small for a pulse with a duration of less than twice the delay time of the measurement cable; (2) the initial division ratio and the stable division ratio of the circuit are the same. Two matched methods of the circuit are acquired, including the first-order matched method and the second-order matched method. Numerical simulations are carried out. According to the simulation results, the relative errors of the circuits with a cable of 20 m are less than 1.5%, obtained by using both match methods for measurement of rectangular pulses with rise and fall times of 5 ns. An improved circuit is presented, which is suitable for any situation where the low-voltage capacitance of the capacitive divider is even smaller than the capaictance of the measurement cable. A verification experment is carried out, and the test result confirms the simulation result.

  17. Characterization of interdigitated electrode structures for water contaminant detection using a hybrid voltage divider and a vector network analyzer.

    Science.gov (United States)

    Rodríguez-Delgado, José Manuel; Rodríguez-Delgado, Melissa Marlene; Mendoza-Buenrostro, Christian; Dieck-Assad, Graciano; Omar Martínez-Chapa, Sergio

    2012-01-01

    Interdigitated capacitive electrode structures have been used to monitor or actuate over organic and electrochemical media in efforts to characterize biochemical properties. This article describes a method to perform a pre-characterization of interdigitated electrode structures using two methods: a hybrid voltage divider (HVD) and a vector network analyzer (VNA). Both methodologies develop some tests under two different conditions: free air and bi-distilled water media. Also, the HVD methodology is used for other two conditions: phosphate buffer with laccase (polyphenoloxidase; EC 1.10.3.2) and contaminated media composed by a mix of phosphate buffer and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The purpose of this study is to develop and validate a characterization methodology using both, a hybrid voltage divider and VNA T-# network impedance models of the interdigitated capacitive electrode structure that will provide a shunt RC network of particular interest in detecting the amount of contamination existing in the water solution for the media conditions. This methodology should provide us with the best possible sensitivity in monitoring water contaminant media characteristics. The results show that both methods, the hybrid voltage divider and the VNA methodology, are feasible in determining impedance modeling parameters. These parameters can be used to develop electric interrogation procedures and devices such as dielectric characteristics to identify contaminant substances in water solutions.

  18. Composition Estimation in Dividing-Wall Columns Using Temperature Measurements

    OpenAIRE

    Ghadrdan, Maryam; Ivar J. Halvorsen; Skogestad, Sigurd

    2011-01-01

    In this work, we propose a method to estimate the product compositions in a distillation column section based on a combination of a number of temperature measurements from different locations in the column stages.

  19. Temperature Induced Voltage Offset Drifts in Silicon Carbide Pressure Sensors

    Science.gov (United States)

    Okojie, Robert S.; Lukco, Dorothy; Nguyen, Vu; Savrun, Ender

    2012-01-01

    We report the reduction of transient drifts in the zero pressure offset voltage in silicon carbide (SiC) pressure sensors when operating at 600 C. The previously observed maximum drift of +/- 10 mV of the reference offset voltage at 600 C was reduced to within +/- 5 mV. The offset voltage drifts and bridge resistance changes over time at test temperature are explained in terms of the microstructure and phase changes occurring within the contact metallization, as analyzed by Auger electron spectroscopy and field emission scanning electron microscopy. The results have helped to identify the upper temperature reliable operational limit of this particular metallization scheme to be 605 C.

  20. High Voltage Resistive Divider Based on Cast Microwire in Glass Insulation on 6–24 kV Alternating Current of Commercial Frequency.

    Directory of Open Access Journals (Sweden)

    Juravleov A.

    2008-12-01

    Full Text Available It is presented the analysis and description of the construction of the high voltage resistive divider on the base of cast microwire in glass insulation on 6–24 kV alternating current of commercial frequency. It is presented the procedure of compensation of frequency error during the process of fabrication of divides and results of tests of the sample model of the divider as well.

  1. Temperature and voltage measurement in quantum systems far from equilibrium

    Science.gov (United States)

    Shastry, Abhay; Stafford, Charles A.

    2016-10-01

    We show that a local measurement of temperature and voltage for a quantum system in steady state, arbitrarily far from equilibrium, with arbitrary interactions within the system, is unique when it exists. This is interpreted as a consequence of the second law of thermodynamics. We further derive a necessary and sufficient condition for the existence of a solution. In this regard, we find that a positive temperature solution exists whenever there is no net population inversion. However, when there is a net population inversion, we may characterize the system with a unique negative temperature. Voltage and temperature measurements are treated on an equal footing: They are simultaneously measured in a noninvasive manner, via a weakly coupled thermoelectric probe, defined by requiring vanishing charge and heat dissipation into the probe. Our results strongly suggest that a local temperature measurement without a simultaneous local voltage measurement, or vice versa, is a misleading characterization of the state of a nonequilibrium quantum electron system. These results provide a firm mathematical foundation for voltage and temperature measurements far from equilibrium.

  2. Temperature Stabilized Characterization of High Voltage Power Supplies

    CERN Document Server

    Krarup, Ole

    2017-01-01

    High precision measurements of the masses of nuclear ions in the ISOLTRAP experiment relies on an MR-ToF. A major source of noise and drift is the instability of the high voltage power supplies employed. Electrical noise and temperature changes can broaden peaks in time-of-flight spectra and shift the position of peaks between runs. In this report we investigate how the noise and drift of high-voltage power supplies can be characterized. Results indicate that analog power supplies generally have better relative stability than digitally controlled ones, and that the high temperature coefficients of all power supplies merit efforts to stabilize them.

  3. 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...

  4. Current-voltage-temperature characteristics of DNA origami

    Energy Technology Data Exchange (ETDEWEB)

    Bellido, Edson P; Bobadilla, Alfredo D; Rangel, Norma L; Seminario, Jorge M [Department of Chemical Engineering, Texas A and M University, College Station, TX 77843 (United States); Zhong Hong; Norton, Michael L [Department of Chemistry, Marshall University, Huntington, WV 25755 (United States); Sinitskii, Alexander [Department of Chemistry, Rice University, Houston, TX 77005 (United States)

    2009-04-29

    The temperature dependences of the current-voltage characteristics of a sample of triangular DNA origami deposited in a 100 nm gap between platinum electrodes are measured using a probe station. Below 240 K, the sample shows high impedance, similar to that of the substrate. Near room temperature the current shows exponential behavior with respect to the inverse of temperature. Sweep times of 1 s do not yield a steady state; however sweep times of 450 s for the bias voltage secure a steady state. The thermionic emission and hopping conduction models yield similar barriers of {approx}0.7 eV at low voltages. For high voltages, the hopping conduction mechanism yields a barrier of 0.9 eV and the thermionic emission yields 1.1 eV. The experimental data set suggests that the dominant conduction mechanism is hopping in the range 280-320 K. The results are consistent with theoretical and experimental estimates of the barrier for related molecules.

  5. Thermo-voltage measurements of atomic contacts at low temperature

    Directory of Open Access Journals (Sweden)

    Ayelet Ofarim

    2016-05-01

    Full Text Available We report the development of a novel method to determine the thermopower of atomic-sized gold contacts at low temperature. For these measurements a mechanically controllable break junction (MCBJ system is used and a laser source generates a temperature difference of a few kelvins across the junction to create a thermo-voltage. Since the temperature difference enters directly into the Seebeck coefficient S = −ΔV/ΔT, the determination of the temperature plays an important role. We present a method for the determination of the temperature difference using a combination of a finite element simulation, which reveals the temperature distribution of the sample, and the measurement of the resistance change due to laser heating of sensor leads on both sides next to the junction. Our results for the measured thermopower are in agreement with recent reports in the literature.

  6. Numerical Electric Field Analysis of Power Status Sensor Observing Power Distribution System Taking into Account Voltage Divider Measurement Circuit

    Science.gov (United States)

    Kubo, Takuro; Furukawa, Tatsuya; Itoh, Hideaki; Fukumoto, Hisao; Wakuya, Hiroshi; Ohchi, Masashi

    We have proposed and preproducted the voltage-current waveform sensor of resin molded type for measuring the power factor and harmonics in power distribution systems. We have executed numerical electromagnetic analyses using the finite element method to estimate the characteristics and behaviours of the sensor. Although the magnetic field analyses for the current sensor have involved the measurement circuit, the electric field analyses have not included the measurement circuit for measuring voltage waveforms of power lines. In this paper, we describe the electric field analyses with the measurement circuit and prove the insulating strength of the proposed sensor permissible to the use in 22kV power distribution systems.

  7. A novel voltage output integrated circuit temperature sensor

    Institute of Scientific and Technical Information of China (English)

    吴晓波; 方志刚; 等

    2002-01-01

    The novel integrated circuit(IC) temperature sensor presented in this paper works similarly as a two-terminal Zener,has breakdown voltage directly proportional to Kelvin temperature at 10mV/℃,with typical error of less tha ±1.0℃ over a temperature range from-50℃to +120℃ .In addition to all the features that conventional IC temperature sensors have,the new device also has very low static power dissipation(0.5mW),low output impedance(less than 1Ω),execllent stability,high reproducibility,and high precision.The sensor's circuit design and layout are discussed in detail.Applications of the sensor include almost and type of temperature sensing over the range of -50℃-+125℃。The low impedance and linear output of the device make interfacing the readout or control circuitry especially easy.Due to the excellent performance and low cost of this sensor.more application of the sensor over wide temperature range are expected.

  8. A novel voltage output integrated circuit temperature sensor

    Institute of Scientific and Technical Information of China (English)

    吴晓波; 赵梦恋; 严晓浪; 方志刚

    2002-01-01

    The novel integrated circuit (IC) temperature sensor presented in this paper works similarly as a two-terminal Zener, has breakdown voltage directly proportional to Kelvin temperature at 10 mV/℃, with typical error of less than ±1.0℃ over a temperature range from -50℃ to +125℃. In addition to all the features that conventional IC temperature sensors have, the new device also has very low static power dissipation ( 0.5 mW ) , low output impedance ( less than 1Ω), excellent stability, high reproducibility, and high precision. The sensor's circuit design and layout are discussed in detail. Applications of the sensor include almost any type of temperature sensing over the range of -50℃-+125℃. The low impedance and linear output of the device make interfacing the readout or control circuitry especially easy. Due to the excellent performance and low cost of this sensor, more applications of the sensor over wide temperature range are expected.

  9. 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...

  10. Variable Temperature Current-Voltage Measurements of CdTe Solar Cells

    Science.gov (United States)

    Smith, A. D.

    2000-03-01

    We have used a 2" x 2" Peltier heat pump chip powered with 24 V from a computer power supply to build a variable temperature stage for current voltage measurements of solar cells. A voltage divider was used to achieve several different set point temperatures from 25 oC to -24 oC. This system was used with a halogen lamp to study the electrical performance of polycrystalline thin-film solar cells fabricated in our group. These cells have the superstrate structure glass/SnO2:F/CdS/CdTe/metal.(1) The I-V characteristic shows evidence of a blocking back-diode which sets in below room temperature. This behavior will be related to the diffusion into the CdTe of the metals used for our back contact.(2) 1. M. Shao, A. Fischer, D. Grecu, U. Jayamaha, E. Bykov, G. Contreras-Puente, R.G. Bohn, and A.D. Compaan, Appl. Phys. Lett. 69, 3045-3047 (1996). 2. D. Grecu and A.D. Compaan, Appl. Phys. Lett. 75, 361-363 (1999).

  11. Optimization of Temperature Coefficient and Noise Analysis of MOSFET- Only Voltage Reference Circuit

    Directory of Open Access Journals (Sweden)

    Arathi.p

    2016-09-01

    Full Text Available The optimization of temperature coefficient and comparison of output noise of two MOSFET only voltage references are introduced. The circuit behavior is analytically described and the performance of the proposed circuits are confirmed through 180nm CMOS technology in virtuoso and the simulation results are presented. Both the circuits can be operated with supply voltage varies from 0.5-1.2V.The output voltage references varied over a temperature range of -25℃ to 50℃.

  12. Temperature and voltage coupling to channel opening in transient receptor potential melastatin 8 (TRPM8).

    Science.gov (United States)

    Raddatz, Natalia; Castillo, Juan P; Gonzalez, Carlos; Alvarez, Osvaldo; Latorre, Ramon

    2014-12-19

    Expressed in somatosensory neurons of the dorsal root and trigeminal ganglion, the transient receptor potential melastatin 8 (TRPM8) channel is a Ca(2+)-permeable cation channel activated by cold, voltage, phosphatidylinositol 4,5-bisphosphate, and menthol. Although TRPM8 channel gating has been characterized at the single channel and macroscopic current levels, there is currently no consensus regarding the extent to which temperature and voltage sensors couple to the conduction gate. In this study, we extended the range of voltages where TRPM8-induced ionic currents were measured and made careful measurements of the maximum open probability the channel can attain at different temperatures by means of fluctuation analysis. The first direct measurements of TRPM8 channel temperature-driven conformational rearrangements provided here suggest that temperature alone is able to open the channel and that the opening reaction is voltage-independent. Voltage is a partial activator of TRPM8 channels, because absolute open probability values measured with fully activated voltage sensors are less than 1, and they decrease as temperature rises. By unveiling the fast temperature-dependent deactivation process, we show that TRPM8 channel deactivation is well described by a double exponential time course. The fast and slow deactivation processes are temperature-dependent with enthalpy changes of 27.2 and 30.8 kcal mol(-1). The overall Q10 for the closing reaction is about 33. A three-tiered allosteric model containing four voltage sensors and four temperature sensors can account for the complex deactivation kinetics and coupling between voltage and temperature sensor activation and channel opening.

  13. Threshold-voltage bias-temperature instability in commercially-available SiC MOSFETs

    Science.gov (United States)

    Green, Ron; Lelis, Aivars; Habersat, Daniel

    2016-04-01

    This work reports on three important aspects of threshold-voltage instability in SiC power MOSFETs: (1) the threshold-voltage bias-temperature instability observed in commercial devices from two leading manufacturers, (2) a summary of the basic mechanisms driving this instability, and (3) the need for an improved test method for evaluating these devices. Even under significant overstress conditions, no negative threshold-voltage shift was observed in the most-recent-vintage commercial devices from one of the manufacturers during a -15 V, 175 °C negative-bias temperature stress lasting 120 h.

  14. Evaluation of high temperature dielectric films for high voltage power electronic applications

    Science.gov (United States)

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

    1992-01-01

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

  15. Performance of the Micropower Voltage Reference ADR3430 Under Extreme Temperatures

    Science.gov (United States)

    Patterson, Richard L.; Hammoud, Ahmad

    2011-01-01

    Electronic systems designed for use in space exploration systems are expected to be exposed to harsh temperatures. For example, operation at cryogenic temperatures is anticipated in space missions such as polar craters of the moon (-223 C), James Webb Space Telescope (-236 C), Mars (-140 C), Europa (-223 C), Titan (-178 C), and other deep space probes away from the sun. Similarly, rovers and landers on the lunar surface, and deep space probes intended for the exploration of Venus are expected to encounter high temperature extremes. Electronics capable of operation under extreme temperatures would not only meet the requirements of future spacebased systems, but would also contribute to enhancing efficiency and improving reliability of these systems through the elimination of the thermal control elements that present electronics need for proper operation under the harsh environment of space. In this work, the performance of a micropower, high accuracy voltage reference was evaluated over a wide temperature range. The Analog Devices ADR3430 chip uses a patented voltage reference architecture to achieve high accuracy, low temperature coefficient, and low noise in a CMOS process [1]. The device combines two voltages of opposite temperature coefficients to create an output voltage that is almost independent of ambient temperature. It is rated for the industrial temperature range of -40 C to +125 C, and is ideal for use in low power precision data acquisition systems and in battery-powered devices. Table 1 shows some of the manufacturer s device specifications.

  16. Influence of temperature and voltage on electrochemical reduction of graphene oxide

    Indian Academy of Sciences (India)

    Xiuqiang Li; Dong Zhang; Peiying Zhu; Chao Yang

    2014-05-01

    In this paper, the influence of temperature and voltage on direct electrochemical reduction were discussed in detail. Reduced graphene oxide is characterized with X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT–IR) and field emission scanning electron microscopy (FE–SEM). It is found that the reduction degree of graphene oxide (GO) decreases gradually with the increase of applied temperature. The optimal applied temperature found in our experiment is 20 °C; Meanwhile, as the applied voltage increases from 0.1 to 12.5 V, the reduction degree of graphene oxide increases gradually. However, above 2.5 V, increasing voltage has little effect on the reduction degree of graphene oxide.

  17. Optimizing performance per watt on GPUs in High Performance Computing: temperature, frequency and voltage effects

    CERN Document Server

    Price, D C; Barsdell, B R; Babich, R; Greenhill, L J

    2014-01-01

    The magnitude of the real-time digital signal processing challenge attached to large radio astronomical antenna arrays motivates use of high performance computing (HPC) systems. The need for high power efficiency (performance per watt) at remote observatory sites parallels that in HPC broadly, where efficiency is an emerging critical metric. We investigate how the performance per watt of graphics processing units (GPUs) is affected by temperature, core clock frequency and voltage. Our results highlight how the underlying physical processes that govern transistor operation affect power efficiency. In particular, we show experimentally that GPU power consumption grows non-linearly with both temperature and supply voltage, as predicted by physical transistor models. We show lowering GPU supply voltage and increasing clock frequency while maintaining a low die temperature increases the power efficiency of an NVIDIA K20 GPU by up to 37-48% over default settings when running xGPU, a compute-bound code used in radio...

  18. 16nm planar process CMOS SRAM cell design: Analysis of Operating Voltage and Temperature Effect

    Directory of Open Access Journals (Sweden)

    Rohit Sharma

    2013-09-01

    Full Text Available Purpose: CMOS devices are scaling down to nano ranges resulting in increased process variations and short channel effects which not only affect the reliability of the device but also performance expectations. The SRAM design uses the smallest transistors possible and is also susceptible to reliability issues and process variations, making it an ideal benchmark circuit to compare the two technologies [1]. Low power static-random access memories (SRAM have become a critical component in modern VLSI systems. They occupy a large portion of area and accounts for a major component of power consumption in today’s VLSI circuits. In this paper we intend to analyse the performance of a traditional 6T SRAM cell of 16nm Complementary Metal Oxide Semiconductor (CMOS technology with change in Operating Voltage and Temperature. Aim: The aim of the paper is to study the effect of the SNM dependencies on the operating voltage and temperatureApproach: Conventional 6T SRAM are designed using predictive technology model developed by Arizona State University [2] of 16nm planar Low Power CMOS and variation of SNM with operating voltage and temperature are simulated and studied using hspice.Findings: Variations in the operating voltages and temperature strongly impact the stability of an SRAM cell at 16nm. Comparative study is done for predictive 16nm based conventional 6T SRAM cell by varying operating voltage and temperature. A methodology to select operating voltage is suggested which can be used in an early stage of a design cycle to optimise stability margins in nanometer regime

  19. Investigation of Threshold Voltage Variability at High Temperature Using Takeuchi Plot

    Science.gov (United States)

    Tsunomura, Takaaki; Nishida, Akio; Hiramoto, Toshiro

    2010-05-01

    The property of metal-oxide-semiconductor field-effect transistors' (MOSFETs) threshold voltage (VT) variability at high temperature is investigated by evaluating the device matrix array test element group (DMA-TEG). It is revealed that VT variation is lower at high temperature than at room temperature, and that VT at high temperature has a strong correlation with VT at room temperature. The normal property of VT variability both at room and high temperatures is validated using the normal probability plot. The decrease in VT variation at high temperature stems from the reduction of the channel depletion layer width (Wdep). The temperature dependence of VT variation is evaluated using the Takeuchi plot, the VT variation normalization method. It is revealed that the change in BVT, the parameter of VT variation in the Takeuchi plot, is very small with varying temperature.

  20. 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

  1. Monitoring operating temperature and supply voltage in achieving high system dependability

    NARCIS (Netherlands)

    Khan, M.A.; Kerkhoff, Hans G.

    2013-01-01

    System dependability being a set of number of attributes, of which the important reliability, heavily depends on operating temperature and supply voltage. Any change beyond the designed specifications may change the system performance and could result in system reliability and hence dependability

  2. Monitoring operating temperature and supply voltage in achieving high system dependability

    NARCIS (Netherlands)

    Khan, M.A.; Kerkhoff, Hans G.

    2013-01-01

    System dependability being a set of number of attributes, of which the important reliability, heavily depends on operating temperature and supply voltage. Any change beyond the designed specifications may change the system performance and could result in system reliability and hence dependability pr

  3. Monitoring operating temperature and supply voltage in achieving high system dependability

    NARCIS (Netherlands)

    Khan, Muhammad Aamir; Kerkhoff, Hans G.

    2013-01-01

    System dependability being a set of number of attributes, of which the important reliability, heavily depends on operating temperature and supply voltage. Any change beyond the designed specifications may change the system performance and could result in system reliability and hence dependability pr

  4. Resistor divider for high voltage pulse measurement in vacuum%一种在真空中测量脉冲高电压的电阻分压器

    Institute of Scientific and Technical Information of China (English)

    卫兵; 关永超; 卿燕玲; 陈林; 周良骥; 李晔; 丰树平

    2012-01-01

    A resistor divider has been designed for voltage measurement of diode load for 1 MV/100 kA fast linear transformer driver(LTD). The divider is designed with two stages. The primary stage is a column of alternating annular metal grading rings and tapered insulators enclosing a resistive solution of sodium thiosulfate. A middle electrode is connected to the secondary voltage dividing stage. There is a 4 kΩ resistor in series with the 50 Ω input impedance of the attenuator or oscilloscope. The e-quivalent circuit of the divider which includes distributed capacitance and inductance has been calculated. It indicates that the high frequency limit of the divider is about 200 MHz. The divider has been calibrated in-situ using a P6015A probe and a high voltage pulser. The calibration ratio is 5 400 : 1. The voltage of diode load reaches 1. 08 MV when the charging voltage of LTD stage is ±85 kV respectively, according with the simulation of LTD.%为测量快脉冲直线变压器驱动源(LTD)二极管负载的脉冲高电压,设计了在真空环境中使用的电阻分压器.分压器使用绝缘堆结构,采用静电场模拟分析了分压器的电场分布.建立了包含分布参数的等效电路,并进行了频率响应仿真,可得分压器的频响上限为200 MHz.使用标准高压探头对分压器进行在线标定,分压比标定结果为5 400∶1,与设计值相符合.在LTD调试实验中,模块充电85 kV时二极管电压为1.08 MV,与理论估算结果一致.

  5. Temperature dependence of current–voltage characteristics of Au/-GaAs epitaxial Schottky diode

    Indian Academy of Sciences (India)

    R Singh; S K Arora; Renu Tyagi; S K Agarwal; D Kanjilal

    2000-12-01

    The influence of temperature on current–voltage (–) characteristics of Au/-GaAs Schottky diode formed on -GaAs epitaxial layer grown by metal organic chemical vapour deposition technique has been investigated. The dopant concentration in the epitaxial layer is 1 × 1016 cm−3 . The change in various parameters of the diode like Schottky barrier height (SBH), ideality factor and reverse breakdown voltage as a function of temperature in the range 80−300 K is presented. The variation of apparent Schottky barrier height and ideality factor with temperature has been explained considering lateral inhomogeneities in the Schottky barrier height in nanometer scale lengths at the metal–semiconductor interface.

  6. Cryogenic temperature dependence of the voltage transfer characteristics of CMOS inverters

    Science.gov (United States)

    Deen, M. J.

    1988-08-01

    The voltage transfer characteristics of CMOS inverters have been studied in detail as a function of temperature between 77 and 300 K and supply voltages between 2 and 20 V. The logic levels, maximum gain, unity gain points, noise margins and other parameters, such as ( VH - VL), all showed a marked improvement as the temperature was lowered. In particular, for one inverter with a supply of 5 V, the maximum gain increased from 57 to 105, ( VIH - VIL) decreased from 0.50 to 0.28 V and ( VH - VL) increased from 4.46 to 4.75 V on decreasing the temperature from 300 to 77 K. For all the inverters, these and other parameters showed a smooth monotonic improvement as the temperature was lowered. These and the other results obtained can be qualitatively explained as due to an increase in the absolute values in the threshold voltages of the PMOS and NMOS transistors and to an increase in the carrier mobility as the temperature was lowered.

  7. 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.

  8. High-voltage picosecond photoconductor switch based on low-temperature-grown GaAs

    Science.gov (United States)

    Frankel, Michael Y.; Whitaker, John F.; Mourou, Gerard A.; Smith, Frank W.; Calawa, Arthur R.

    1990-01-01

    A GaAs material grown by molecular beam epitaxy at a low substrate temperature was used to fabricate a photoconductor switch that produces 6-V picosecond electrical pulses. The pulses were produced on a microwave coplanar-strip transmission line lithographically patterned on the low-temperature (LT) GaAs. A 150-fs laser pulse was used to generate carriers in the LT GaAs gap between the metal strips, partially shorting a high DC voltage placed across the lines. The 6-V magnitude of the electrical pulses obtained is believed to be limited by the laser pulse power and not by the properties of the LT GaAs. Experiments were also performed on a picosecond photoconductor switch fabricated on a conventional ion-damaged silicon-on-sapphire substrate. Although comparable pulse durations were obtained, the highest pulse voltage achieved with the latter device was 0.6 V.

  9. Increasing the Néel temperature of magnetoelectric chromia for voltage-controlled spintronics

    Science.gov (United States)

    Street, M.; Echtenkamp, W.; Komesu, Takashi; Cao, Shi; Dowben, P. A.; Binek, Ch.

    2014-06-01

    Boron doped chromia (Cr2O3) thin films with substitutional doping levels between zero and 3% are grown using pulsed laser deposition in borane background gases. Magnetometry reveals a tunable increase in the Néel temperature of the (0001) textured Cr2BxO3-x thin films at a rate of about 10% with 1% oxygen site substitution preserving a net boundary magnetization. Spin resolved inverse photoemission measured after magnetoelectric annealing in subsequently reversed electric fields evidences voltage-controlled reversal of boundary magnetization and thus magnetoelectricity of Cr2BxO3-x. Conservation of magnetoelectricity far above room temperature makes ultra-low power voltage-controlled spintronic devices feasible.

  10. System for improving measurement accuracy of transducer by measuring transducer temperature and resistance change using thermoelectric voltages

    Science.gov (United States)

    Anderson, Karl F. (Inventor); Parker, Allen R., Jr. (Inventor)

    1993-01-01

    A constant current loop measuring system measures a property including the temperature of a sensor responsive to an external condition being measured. The measuring system includes thermocouple conductors connected to the sensor, sensing first and second induced voltages responsive to the external condition. In addition, the measuring system includes a current generator and reverser generating a constant current, and supplying the constant current to the thermocouple conductors in forward and reverse directions generating first and second measured voltages, and a determining unit receiving the first and second measured voltages from the current generator and reverser, and determining the temperature of the sensor responsive to the first and second measured voltages.

  11. A Simple Method for Determining the Temperature Coefficient of Voltaic Cell Voltage

    Science.gov (United States)

    Saieed, Alfred E.; Davies, Keith M.

    1996-10-01

    Although use of the Nernst equation to illustrate the dependence of cell potential on half-cell concentrations is routinely covered in first-year college chemistry and high school AP chemistry classes, the temperature dependence of cell voltages is rarely encountered outside of the undergraduate physical chemistry laboratory. Even there, its coverage is somewhat limited because of the cost and sophistication of the instrumentation required. This article describes a relatively simple method for preparing voltaic cells, and through their temperature coefficient, _Eo/_T, it explores relationships between DeltaGo, DeltaHo and DeltaSo for the cell reactions involved.

  12. Influence of carrier flow on the temperature-dependent capacitance-voltage profiles of heterojunction structures

    Science.gov (United States)

    Kwon, S. D.; Lim, H.; Shin, H. K.; Choe, Byung-Doo

    1996-10-01

    We suggest a model which can explain the shifting of carrier concentration peaks in the temperature-dependent capacitance-voltage carrier profiles of heterojunction (HJ) structures. The shift of concentration peaks, which was frequently observed in the inverted isotype HJs was previously attributed to the traps at the heterointerface. The main feature of our model is the role of band offset as a limiter to the test signal current. The model can explain the difference of the peak shift in the carrier profiles of the normal and inverted type HJs. According to this model, the peak shifts at low temperatures occur naturally for the inverted type HJs.

  13. Negative Bias Temperature Instability "Recovery" under Negative Stress Voltage with Different Oxide Thicknesses

    Institute of Scientific and Technical Information of China (English)

    CAO Yan-Rong; MA Xiao-Hua; HAO Yue; ZHU Min-Bo; TIAN Wen-Chao; ZHANG Yue

    2011-01-01

    Different phenomena are observed under negative gate voltage stress which is smaller than the previous degradation stress in PMOSFETs with different oxide thicknesses. We adopt the real time method to make a point of the drain current to study the degradation and recovery of negative bias temperature instability (NBTI). For the device with thin oxide, recovery phenomenon appears when smaller negative voltage stress was applied, due to the more influencing oxide charges detrapping effects than the interface states. For the device with thick oxide, not recovery but degradation phenomenon comes forth. As many charges are trapped in the deeper position and higher energy level in the oxide, these charges can not be detrapped. Therefore, the effect of the charge detrapping is smaller than that of the interface states in the thick oxide. The degradation presents itself during the 'recovery' time.

  14. Temperature current-voltage characterisation of MOCVD grown InGaN/GaN MQW LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Moldovan, Grigore; Humphreys, Colin J. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Phillips, Andrew [phconsult Ltd., 54 Covent Garden, Cambridge, CB1 2HR (United Kingdom); Thrush, E.J. [Thomas Swan Scientific Equipment Limited, Buckingway Business Park, Cambridge, CB4 5UK (United Kingdom)

    2006-06-15

    A methodology of temperature current-voltage characterisation for blue GaN-based LED is described, with emphasis on artefacts arising from self-heating at high forward currents and voltage transients at low forward currents. Examples of LEDs with Al{sub 2}O{sub 3} and SiC substrates are discussed, with methods of accounting and avoiding these errors. For the devices studied here it is found that tunnelling dominates the charge transport and that two parallel conduction pathways are present. A method of interpretation of extracted data is also presented, in the context of desired device performance. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Changes in CdS/CdTe Solar Cells Subjected to Elevated Temperature, Voltage and Illumination

    Science.gov (United States)

    Demtsu, Samuel; Nagle, Tim

    2003-10-01

    CdTe/CdS solar cells have been known to exhibit degradation in performance after being subjected to elevated temperature, voltage and illumination. These conditions are collectively referred to as "stress". We have studied and presented CdTe/CdS cell degradation under different stress conditions of devices from First Solar Inc., the University of South Florida and the University of Toledo. All cells were stressed in the light (close to 100 mW/cm2) for 56 days at elevated temperature of 900C at two different biases, short circuit (SC) and open circuit (OC). The stress condition surpasses the operation conditions expected in the field. To characterize the cells, we have measured current density as function of the applied voltage (JV), capacitance vs bias voltage (CV) and quantum efficiency (QE) measurements before and after exposure to stress. To investigate the spatial non-uniformity of photocurrent collection induced by stress we have done Light Beam-Induced Current (LBIC) measurement. The effect of the stress on the photovoltaic parameters short-circuit current (Jsc), open-circuit voltage (Voc), Fill-Factor (FF), and efficiency is presented and discussed. Carrier density as a function of the distance from the semiconductor junction is extracted from the C-V measurements. We have seen some variations between cells and degradation was not monotonic with stress time. The highly probable explanation for the degradation of the cells after the stress is that mobile copper ions diffuse out of the back contact towards the primary junction leaving a depletion of Cu in the back contact, which increases the contact barrier.

  16. Dividing Discipline

    DEFF Research Database (Denmark)

    Kristensen, Peter Marcus

    2012-01-01

    the periphery of the network—security studies and international political economy in particular—but communication is also divided along the lines of geography and policy/theory. The article concludes that divisions notwithstanding, IR communication remains centered around American, general, and theoretical IR...

  17. 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.

  18. Dividing Discipline

    DEFF Research Database (Denmark)

    Kristensen, Peter Marcus

    2012-01-01

    International Relations (IR) has cultivated an image as a discipline with strong divisions along paradigmatic, methodological, metatheoretical, geographical, and other lines. This article questions that image analyzing the latent structures of communication in IR. It uses citation data from more...... the periphery of the network—security studies and international political economy in particular—but communication is also divided along the lines of geography and policy/theory. The article concludes that divisions notwithstanding, IR communication remains centered around American, general, and theoretical IR...

  19. Effects of vinylene carbonate on high temperature storage of high voltage Li-ion batteries

    Science.gov (United States)

    Eom, Ji-Yong; Jung, In-Ho; Lee, Jong-Hoon

    The effects of vinylene carbonate (VC) on high temperature storage of high voltage Li-ion batteries are investigated. 1.3 M of LiPF 6 dissolved in ethylene carbonate (EC), ethylmethyl carbonate (EMC) and dimethyl carbonate (DMC) of 3:3:4 volume ratio is used as original electrolyte for 18650 cylindrical cells with LiCoO 2 cathode and graphite anode. VC is then added to electrolyte. At the initial stage of the high temperature storage, higher open-circuit voltage (OCV) is maintained when increasing the VC concentration. As the storage time increases, OCV of higher VC concentration drops gradually, and then the gas evolution takes place abruptly. Gas analysis shows methane (CH 4) decreases with increase of the VC concentration due to formation of stable solid electrolyte interface (SEI) layer on the graphite. Since the residual VC after formation of the SEI layer decomposes on the cathode surface, carbon dioxide (CO 2) dramatically increases on the cathode with the VC concentration, leaving poly(VC) film at the anode surface, as suggested by XPS test results.

  20. High-density magnetoresistive random access memory operating at ultralow voltage at room temperature.

    Science.gov (United States)

    Hu, Jia-Mian; Li, Zheng; Chen, Long-Qing; Nan, Ce-Wen

    2011-11-22

    The main bottlenecks limiting the practical applications of current magnetoresistive random access memory (MRAM) technology are its low storage density and high writing energy consumption. Although a number of proposals have been reported for voltage-controlled memory device in recent years, none of them simultaneously satisfy the important device attributes: high storage capacity, low power consumption and room temperature operation. Here we present, using phase-field simulations, a simple and new pathway towards high-performance MRAMs that display significant improvements over existing MRAM technologies or proposed concepts. The proposed nanoscale MRAM device simultaneously exhibits ultrahigh storage capacity of up to 88 Gb inch(-2), ultralow power dissipation as low as 0.16 fJ per bit and room temperature high-speed operation below 10 ns.

  1. Temperature-dependent current-voltage characteristics of niobium SNIS Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Lacquaniti, V; Andreone, D; Cassiago, C; De Leo, N; Fretto, M; Sosso, A [National Institute of Metrological Research, Electromagnetism Division, Strada delle Cacce 91, 10135 Torino (Italy); Belogolovskii, M, E-mail: v.lacquaniti@inrim.i [Donetsk Physical and Technical Institute, National Academy of Sciences of Ukraine, Str. Rosa Luxemburg. 72, 83114 Donetsk (Ukraine)

    2010-06-01

    Motivated by a search for a suitable technology to fabricate Josephson junctions with a tunable damping regime, we performed a systematic study of the temperature effect on the critical current in Nb/Al-AlO{sub x}-Nb heterostructures with a nanometer-thick Al interlayer. For Al layer thicknesses ranging from 40 to 110 nm, we have observed a transition from hysteretic (below 4.2 K) to non-hysteretic (above 4.2 K) current-voltage curves. Measured supercurrent-vs-temperature characteristics which significantly differ from those of traditional SIS and SNS devices are interpreted in terms of the superconducting proximity effect between Al and Nb films. Thermal stability and good reproducibility of our junctions are demonstrated.

  2. Near-room-temperature refrigeration through voltage-controlled entropy change in multiferroics

    Science.gov (United States)

    Binek, Ch.; Burobina, V.

    2013-01-01

    Composite materials with large magnetoelectric effect are proposed for application in advanced near-room-temperature refrigeration. The key innovation rests on utilizing the magnetocaloric effect in zero applied magnetic fields. This approach promises sizable isothermal entropy change and virtually temperature-independent refrigerant capacity through pure voltage-control. It is in sharp contrast with the conventional method of exploiting the magnetocaloric effect through applied magnetic fields. We outline the thermodynamics and estimate an isothermal entropy change specifically for the La0.7Sr0.3MnO3/Pb(Mg1/3Nb2/3)O3-PbTiO3(001) two-phase composite material. Finally, we propose structural variations of two-phase composites, which help in overcoming the challenging task of producing nanostructured material in macroscopic quantities.

  3. Cold wire constant voltage anemometry to measure temperature fluctuations and its application in a thermoacoustic system

    Science.gov (United States)

    Cleve, Sarah; Jondeau, Emmanuel; Blanc-Benon, Philippe; Comte-Bellot, Geneviève

    2017-04-01

    The knowledge of temperature fluctuations is essential for most thermoacoustic systems. In the present paper, cold wire constant-voltage anemometry (CVA) to measure temperature fluctuations is presented. Corrections for the thermal inertia and for the end losses of the wire are applied during the post-processing. The correction for the thermal inertia of the cold wire is achieved by applying a time dependent thermal lag as proposed originally for a constant-current anemometry (CCA) system. This thermal lag is measured in parallel by a hot wire. The thermal end losses of the wires to their supports are also considered and approximate corrections are proposed. The procedure for the cold wire CVA is validated in the acoustic field of an acoustic resonator with wires of different lengths. A comparison between a CVA and a CCA measurement also confirms the CVA measurement. Furthermore, the proposed measurement procedure is applied close to the stack of a thermoacoustic refrigerator. Supposing a two-dimensional flow, the simultaneous measurement of velocity and temperature fluctuations is possible. This allows a detailed examination of the acoustic field close to the stack, including the study of the correlation between temperature and velocity.

  4. Effect of temperature on the current (capacitance and conductance)–voltage characteristics of Ti/n-GaAs diode

    Energy Technology Data Exchange (ETDEWEB)

    Ejderha, K. [Department of Electricity and Energy, Vocational High School of Technical Sciences, Bingol University, 12000 Bingol (Turkey); Duman, S., E-mail: sduman@atauni.edu.tr; Urhan, F. [Department of Physics, Faculty of Sciences, Ataturk University, 25240 Erzurum (Turkey); Nuhoglu, C. [Department of Physics, Faculty of Sciences, Yildiz Technical University, 34220 Istanbul (Turkey); Turut, A. [Department of Engineering Physics, Faculty of Sciences, Istanbul Medeniyet University, 34700 Istanbul (Turkey)

    2014-12-21

    In this study, Ti/n-GaAs Schottky barrier diode has been fabricated by DC magnetron sputtering. The current–voltage, capacitance–voltage, and conductance–voltage characteristics of Ti/n–GaAs diode have been investigated in the temperature range of 80–320 K. The ideality factor and barrier height values have been calculated from the forward current–voltage characteristics. The variation of the diode parameters with the sample temperature has been attributed to the presence of the lateral inhomogeneities of the barrier height. The temperature dependent capacitance–voltage characteristics have been measured to calculate the carrier concentration, diffusion potential, barrier height, and temperature coefficient of the barrier height (α = −0.65 meV K{sup −1}). The fact that the temperature coefficient of the barrier height changes from metal to metal has been ascribed to the chemical nature of the contact metal or metal electronegativity.

  5. 农用高压电网圆柱形殷钢电容分压器边缘效应的研究%Application Study of Agricultural High-voltage Grid of Cylindrical Invar on Capacitive Divider Edge Effects

    Institute of Scientific and Technical Information of China (English)

    董赫; 李伟凯

    2015-01-01

    By comparing the calculated value and actual measurement value of invar on the capacitive voltage divider,the presence of edge effects caused the actual results was too large capacitive divider conclusions. The theoretical analysis was used as a starting point and combined with calculus theory and capacitors idea,and the edge effects formula of the total capacitance value was derived. According to the characteristics of the cylindrical capacitor,the approach of increasing the capacitive divider edge capacitance on the ring chamfer radius was provided to weaken the edge effect,and the test had been passed to verify the program feasibility.%通过殷钢电容分压器理论计算值与实际测量值的对比,得到边缘效应的存在导致电容分压器的实际测量值偏大的结论。以理论分析为切入点,结合微积分原理及电容串联思想,推导出计及边缘效应的分压器电容值计算公式。针对圆柱形电容器的特点,提出利用增加电容分压器边缘电容环倒角半径的方法来削弱边缘效应,并通过试验验证了该方案的可行性。

  6. Effect of temperature and loading on output voltage of lead zirconate titanate (PZT-5A) piezoelectric energy harvester

    Science.gov (United States)

    Butt, Z.; Pasha, R. A.

    2016-08-01

    Energy harvesting is the process of acquiring energy from the external sources and then further used to drive any system. Piezoelectric material was operated at various temperature but the characterization of the material mostly performed at room temperature. The depolarization in piezoelectric material occurs when the material is heated to its curie temperature and when mechanical stresses are high to disturb the properties of the material. The aim of this paper is to study the performance of lead zirconate titanate (PZT-5A) piezoelectric material under various temperatures and loading conditions. The output voltage of piezoelectric material decreases with increase of temperature. It was found that output voltage from the harvester increases when loading increases while its temperature decreases.

  7. High-Voltage 1-kW dc/dc Converter Developed for Low-Temperature Operation

    Science.gov (United States)

    Patterson, Richard L.

    1998-01-01

    Recently, Lewis developed and demonstrated a high-voltage, 1-kW dc/dc converter that operates from room temperature to -184 C. A power supply designed for use in a NASA ion beam propulsion system was utilized as a starting point for the design of a low- (wide-) temperature dc/dc converter. For safety, we decided to halve the output voltage and power level, so the converter was designed for an 80-Vdc input and a 550-Vdc output at 1 kW.

  8. Modelling and simulation of double chamber microbial fuel cell. Cell voltage, power density and temperature variation with process parameters

    Energy Technology Data Exchange (ETDEWEB)

    Shankar, Ravi; Mondal, Prasenjit; Chand, Shri [Indian Institute of Technology Roorkee, Uttaranchal (India). Dept. of Chemical Engineering

    2013-11-01

    In the present paper steady state models of a double chamber glucose glutamic acid microbial fuel cell (GGA-MFC) under continuous operation have been developed and solved using Matlab 2007 software. The experimental data reported in a recent literature has been used for the validation of the models. The present models give prediction on the cell voltage and cell power density with 19-44% errors, which is less (up to 20%) than the errors on the prediction of cell voltage made in some recent literature for the same MFC where the effects of the difference in pH and ionic conductivity between anodic and cathodic solutions on cell voltage were not incorporated in model equations. It also describes the changes in anodic and cathodic chamber temperature due to the increase in substrate concentration and cell current density. Temperature profile across the membrane thickness has also been studied. (orig.)

  9. Sign of inverse spin Hall voltages generated by ferromagnetic resonance and temperature gradients in yttrium iron garnet platinum bilayers

    NARCIS (Netherlands)

    Schreier, Michael; Bauer, Gerrit E. W.; Vasyuchka, Vitaliy I.; Flipse, Joost; Uchida, Ken-ichi; Lotze, Johannes; Lauer, Viktor; Chumak, Andrii V.; Serga, Alexander A.; Daimon, Shunsuke; Kikkawa, Takashi; Saitoh, Eiji; van Wees, Bart J.; Hillebrands, Burkard; Gross, Rudolf; Goennenwein, Sebastian T. B.

    2015-01-01

    We carried out a concerted effort to determine the absolute sign of the inverse spin Hall effect voltage generated by spin currents injected into a normal metal. We focus on yttrium iron garnet (YIG)vertical bar platinum bilayers at room temperature, generating spin currents by microwaves and temper

  10. Temperature- and supply voltage-independent time references for wireless sensor networks

    CERN Document Server

    De Smedt, Valentijn; Dehaene, Wim

    2015-01-01

    This book investigates the possible circuit solutions to overcome the temperature- and supply voltage-sensitivity of fully-integrated time references for ultra-low-power communication in wireless sensor networks. The authors provide an elaborate theoretical introduction and literature study to enable full understanding of the design challenges and shortcomings of current oscillator implementations.  Furthermore, a closer look to the short-term as well as the long-term frequency stability of integrated oscillators is taken. Next, a design strategy is developed and applied to 5 different oscillator topologies and 1 sensor interface.All 6 implementations are subject to an elaborate study of frequency stability, phase noise, and power consumption. In the final chapter all blocks are compared to the state of the art. The main goals of this book are: • to provide a comprehensive overview of timing issues and solutions in wireless sensor networks; • to gain understanding of all underlying mechanisms by starti...

  11. Studies on temperature dependence of current-voltage characteristics of glancing angle deposited indium oxide nanowire on silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Aniruddha, E-mail: aniruddhamo@gmail.com; Das, Amit Kumar [Department of Physics, National Institute of technology Durgapur, Mahatma Gandhi Rd, A-Zone, Durgapur, West Bengal, India-713209 (India); Dey, Anubhab [Indian Institute of Science Education and Research, Thiruvananthapuram, Computer Science Building, College of Engineering Trivandrum Campus, Thiruvananthapuram, Kerala 695016 (India); Choudhuri, Bijit [Department of Electronics & Communication Engineering, National Institute of Technology Agartala, Jirania, Tripura, India - 799046 (India)

    2016-05-06

    The 1D perpendicular In{sub 2-x}O{sub 3-y} nanostructure arrays have been synthesized by using glancing angle deposition (GLAD) technique. A low deposition rate of 0.5 A°/S produced highly porous structure. The current - voltage characteristics for the In{sub 2-x}O{sub 3-y}nanocolumnar array based were measured through a gold Schottky contact at different temperatures. The temperature dependent ideality factor was calculated from the observed current – voltage characteristics. The ideality factor was found to vary from 4.19 to 2.75 with a variation in temperature from 313 K to 473 K.

  12. Substrate bias voltage and deposition temperature dependence on properties of rf-magnetron sputtered titanium films on silicon (100)

    Indian Academy of Sciences (India)

    B Geetha Priyadarshini; Shampa Aich; Madhusudan Chakraborty

    2014-12-01

    Thin films or a coating of any sort prior to its application into real world has to be studied for the dependence of process variables on their structural and functional properties. One such study based on the influence of substrate conditions viz. substrate-bias voltage and substrate temperature on the structural and morphological properties, could be of great interest as far as Ti thin films are concerned. From X-ray texture pole figure and electron microscopy analysis, it was found that substrate bias voltage strongly influence preferential orientation and morphology of Ti films grown on Si (100) substrate. Deposition at higher substrate temperature causes the film to react with Si forming silicides at the film/Si substrate interface. Ti film undergoes a microstructural transition from hexagonal plate-like to round-shaped grains as the substrate temperature was raised from 300 to 50 °C during film deposition.

  13. Apparatus and Method for Compensating for Process, Voltage, and Temperature Variation of the Time Delay of a Digital Delay Line

    Science.gov (United States)

    Seefeldt, James (Inventor); Feng, Xiaoxin (Inventor); Roper, Weston (Inventor)

    2013-01-01

    A process, voltage, and temperature (PVT) compensation circuit and a method of continuously generating a delay measure are provided. The compensation circuit includes two delay lines, each delay line providing a delay output. The two delay lines may each include a number of delay elements, which in turn may include one or more current-starved inverters. The number of delay lines may differ between the two delay lines. The delay outputs are provided to a combining circuit that determines an offset pulse based on the two delay outputs and then averages the voltage of the offset pulse to determine a delay measure. The delay measure may be one or more currents or voltages indicating an amount of PVT compensation to apply to input or output signals of an application circuit, such as a memory-bus driver, dynamic random access memory (DRAM), a synchronous DRAM, a processor or other clocked circuit.

  14. Open-circuit voltage analysis of p-i-n type amorphous silicon solar cells deposited at low temperature

    Institute of Scientific and Technical Information of China (English)

    Ni Jian; Zhang Jian-Jun; Cao Yu; Wang Xian-Bao; Li Chao; Chen Xin-Liang; Geng Xin-Hua; Zhao Ying

    2011-01-01

    This paper identifies the contributions of p-a-SiC:H layers and i-a-Si:H layers to the open circuit voltage of p-i-n type a-Si:H solar cells deposited at a low temperature of 125 ℃.We find that poor quality p-a-SiC:H films under regular conditions lead to a restriction of open circuit voltage although the band gap of the i-layer varies widely.A significant improvement in open circuit voltage has been obtained by using high quality p-a-SiC:H films optimized at the "low-power regime" under low silane flow rates and high hydrogen dilution conditions.

  15. Voltage- and temperature-dependent allosteric modulation of alpha7 nicotinic receptors by PNU120596

    Directory of Open Access Journals (Sweden)

    Fabrio eSitzia

    2011-12-01

    Full Text Available Alpha7 nicotinic receptors (a7nAChR are widely distributed throughout the central nervous system (CNS and are found at particularly high levels in the hippocampus and cortex. Several lines of evidence indicate that pharmacological enhancement of a7nAChRs function could be a potential therapeutic route to alleviate disease-related cognitive deficits. A recent pharmacological approach adopted to increase a7nAChR activity has been to identify selective positive allosteric modulators (PAMs. a7nAChR PAMs have been divided into two classes: type I PAMs increase agonist potency with only subtle effects on kinetics, whereas type II agents produce additional dramatic effects on desensitization and deactivation kinetics. Here we report novel observations concerning the pharmacology of the canonical type II PAM, PNU120596. Using patch clamp analysis of acetylcholine (ACh-mediated currents through recombinant rat a7nAChR we show that positive allosteric modulation measured in two different ways is greatly attenuated when the temperature is raised to near physiological levels. Furthermore, PNU120596 largely removes the strong inward rectification usually exhibited by a7nAChR-mediated responses.

  16. Analogue Divider by Averaging a Triangular Wave

    Science.gov (United States)

    Selvam, Krishnagiri Chinnathambi

    2017-08-01

    A new analogue divider circuit by averaging a triangular wave using operational amplifiers is explained in this paper. The triangle wave averaging analog divider using operational amplifiers is explained here. The reference triangular waveform is shifted from zero voltage level up towards positive power supply voltage level. Its positive portion is obtained by a positive rectifier and its average value is obtained by a low pass filter. The same triangular waveform is shifted from zero voltage level to down towards negative power supply voltage level. Its negative portion is obtained by a negative rectifier and its average value is obtained by another low pass filter. Both the averaged voltages are combined in a summing amplifier and the summed voltage is given to an op-amp as negative input. This op-amp is configured to work in a negative closed environment. The op-amp output is the divider output.

  17. CMOS temperature sensor using a resistively degenerated common-source amplifier biased by an adjustable proportional-to-absolute-temperature voltage

    Science.gov (United States)

    Wang, Ruey-Lue; Fu, Chien-Cheng; Yu, Chi; Hao, Yi-Fan; Shi, Jian-Liang; Lin, Chen-Fu; Liao, Hsin-Hao; Tsai, Hann-Huei; Juang, Ying-Zong

    2014-01-01

    A high-linearity CMOS temperature sensor with pulse output is presented. The temperature core is a resistively degenerated common-source amplifier which gate is biased by a proportional-to-absolute-temperature (PTAT) voltage generator. The source resistor is made of polysilicon which resistance has a PTAT characteristic. The current flowing through the resistor exhibits a PTAT characteristic with high linearity of 99.99% at least for a temperature range from 0 to 125 °C. The PTAT voltage generator can be adjusted by a bias voltage Vb and hence the PTAT current can also be adjusted by the Vb. The PTAT current is mirrored to an added current controlled oscillator which output pulse frequencies also exhibit a PTAT characteristic. For the chip using the 0.35 µm process, the plots of measured pulse frequencies against temperature exhibit the sensitivity of 2.30 to 2.24 kHz/°C with linearity of more than 99.99% at the Vb of 1 to 1.2 V.

  18. Method and apparatus for connecting high voltage leads to a high temperature super-conducting transformer

    Science.gov (United States)

    Golner, Thomas M.; Mehta, Shirish P.

    2005-07-26

    A method and apparatus for connecting high voltage leads to a super-conducting transformer is provided that includes a first super-conducting coil set, a second super-conducting coil set, and a third super-conducting coil set. The first, second and third super-conducting coil sets are connected via an insulated interconnect system that includes insulated conductors and insulated connectors that are utilized to connect the first, second, and third super-conducting coil sets to the high voltage leads.

  19. Fabrication of hemispherical nano structure on a curved Al surface using low-temperature and high-voltage anodizing method.

    Science.gov (United States)

    Shin, H G; Park, Y M; Kim, B H; Seo, Y H

    2011-01-01

    A simple method of fabricating hemispherical nanostructures on a curved aluminum rod surface was presented. In conventional methods of fabricating nanopatterns on a curved aluminum surface, mechanical or chemical processes have been widely used for the lens technologies. Such processes are not only expensive with long processing times, however, but they also involve local fabrication and are limited in the dimension size. In this paper, a method of fabricating hemispherical nanostructures on a curved aluminum surface is suggested for a functional three-dimensional (3D) master using a low-temperature and high-voltage (LTHV) anodizing method. By reducing the aluminum reaction rate under a low-temperature environment, the reaction current density can be remarkably reduced even though a high voltage was induced. Using the LTHV anodizing method, the hemispherical pattern size can be easily controlled with respect to voltage variations. The sizes of the hemispherical nanopatterns were about 150-300 nm. Using the LTHV anodizing process, hemispherical nanostructures can be obtained on a curved aluminum surface with controllable pattern sizes of 150-300 nm without defects such as burring from Joule's heat, micro-scratches, and cracks. A curved 3D hemispherical nanostructure may be used as a master in the roll-to-roll process.

  20. Reduced junction temperature control during low-voltage ride-through for single-phase photovoltaic inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    Future photovoltaic (PV) inverters are expected to comply with more stringent grid codes and reliability requirements, especially when a high penetration degree is reached, and also to lower the cost of energy. A junction temperature control concept is proposed in this study for the switching...... devices in a single-phase PV inverter in order to reduce the junction temperature stress, and thus to achieve improved reliability of a PV inverter. The thermal stresses of the switching devices are analysed during low voltage ride-through operation with different levels of reactive power injection......, allowing an optimal design of the proposed control scheme with controlled mean junction temperature and reduced junction temperature swings. The effectiveness of the control method in terms of both thermal performance and electrical performance is validated by the simulations and experiments, respectively...

  1. Temperature dependence of current-and capacitance-voltage characteristics of an Au/4H-SiC Schottky diode

    Science.gov (United States)

    Gülnahar, Murat

    2014-12-01

    In this study, the current-voltage (I-V) and capacitance-voltage (C-V) measurements of an Au/4H-SiC Schottky diode are characterized as a function of the temperature in 50-300 K temperature range. The experimental parameters such as ideality factor and apparent barrier height presents to be strongly temperature dependent, that is, the ideality factor increases and the apparent barrier height decreases with decreasing temperature, whereas the barrier height values increase with the temperature for C-V data. Likewise, the Richardson plot deviates at low temperatures. These anomaly behaviors observed for Au/4H-SiC are attributed to Schottky barrier inhomogeneities. The barrier anomaly which relates to interface of Au/4H-SiC is also confirmed by the C-V measurements versus the frequency measured in 300 K and it is interpreted by both Tung's lateral inhomogeneity model and multi-Gaussian distribution approach. The values of the weighting coefficients, standard deviations and mean barrier height are calculated for each distribution region of Au/4H-SiC using the multi-Gaussian distribution approach. In addition, the total effective area of the patches NAe is obtained at separate temperatures and as a result, it is expressed that the low barrier regions influence meaningfully to the current transport at the junction. The homogeneous barrier height value is calculated from the correlation between the ideality factor and barrier height and it is noted that the values of standard deviation from ideality factor versus q/3kT curve are in close agreement with the values obtained from the barrier height versus q/2kT variation. As a result, it can be concluded that the temperature dependent electrical characteristics of Au/4H-SiC can be successfully commented on the basis of the thermionic emission theory with both models.

  2. Time dependent and temperature dependent properties of the forward voltage characteristic of InGaN high power LEDs

    Directory of Open Access Journals (Sweden)

    P. L. Fulmek

    2017-03-01

    Full Text Available Estimating the junction temperature and its dynamic behavior in dependence of various operating conditions is an important issue, since these properties influence the optical characteristics as well as the aging processes of a light-emitting diode (LED. Particularly for high-power LEDs and pulsed operation, the dynamic behavior and the resulting thermal cycles are of interest. The forward voltage method relies on the existence of a time-independent unique triple of forward-voltage, forward-current, and junction temperature. These three figures should as well uniquely define the optical output power and spectrum, as well as the loss power of the LED, which is responsible for an increase of the junction temperature. From transient FEM-simulations one may expect an increase of the temperature of the active semiconductor layer of some 1/10 K within the first 10 μs. Most of the well-established techniques for junction temperature measurement via forward voltage method evaluate the measurement data several dozens of microseconds after switching on or switching off and estimate the junction temperature by extrapolation towards the time of switching. In contrast, the authors developed a measurement procedure with the focus on the first microseconds after switching. Besides a fast data acquisition system, a precise control of the switching process is required, i.e. a precisely defined current pulse amplitude with fast rise-time and negligible transient by-effects. We start with a short description of the measurement setup and the newly developed control algorithm for the generation of short current pulses. The thermal characterization of the LED chip during the measurement procedures is accomplished by an IR thermography system and transient finite element simulations. The same experimental setup is used to investigate the optical properties of the LED in an Ulbricht-sphere. Our experiments are performed on InGaN LED chips mounted on an Al based

  3. A facile approach to derive binder protective film on high voltage spinel cathode materials against high temperature degradation

    Science.gov (United States)

    Chou, Wei-Yu; Jin, Yi-Chun; Duh, Jenq-Gong; Lu, Cheng-Zhang; Liao, Shih-Chieh

    2015-11-01

    The electrochemical performance of spinel LiNi0.5Mn1.5O4 cathode combined with different binders at elevated temperature is firstly investigated. The water soluble binder, such as sodium carboxymethyl cellulose (CMC) and sodium alginate (SA), is compared with the polyvinylidene difluoride (PVdF) binder used in non-aqueous process. The aqueous process can meet the need of Li-ion battery industry due to environmental-friendly and cost effectiveness by replacing toxic organic solvent, such as N-methyl-pyrrolidone (NMP). In this study, a significantly improved high temperature cycling performance is successfully obtained as compared to the traditional PVdF binder. The aqueous binder can serve as a protective film which inhibits the serious Ni and Mn dissolution especially at elevated temperature. Our result demonstrates a facile approach to solve the problem of capacity fading for high voltage spinel cathodes.

  4. Temperature and bias voltage dependence of Co/Pd multilayer-based magnetic tunnel junctions with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, Zoe, E-mail: zkugler@physik.uni-bielefeld.d [Bielefeld University, Department of Physics, Universitaetsstr. 25, 33615 Bielefeld (Germany); Drewello, Volker; Schaefers, Markus; Schmalhorst, Jan; Reiss, Guenter; Thomas, Andy [Bielefeld University, Department of Physics, Universitaetsstr. 25, 33615 Bielefeld (Germany)

    2011-01-15

    Temperature- and bias voltage-dependent transport measurements of magnetic tunnel junctions (MTJs) with perpendicularly magnetized Co/Pd electrodes are presented. Magnetization measurements of the Co/Pd multilayers are performed to characterize the electrodes. The effects of the Co layer thickness in the Co/Pd bilayers, the annealing temperature, the Co thickness at the MgO barrier interface, and the number of bilayers on the tunneling magneto resistance (TMR) effect are investigated. TMR-ratios of about 11% at room temperature and 18.5% at 13 K are measured and two well-defined switching fields are observed. The results are compared to measurements of MTJs with Co-Fe-B electrodes and in-plane anisotropy.

  5. Two phase multiferroics for voltage-induced entropy change with application in near-room-temperature refrigeration

    Science.gov (United States)

    Giri, Prakash; Kumar, Dhananjay; Binek, Christian

    The demand for environmental friendly, cost-effective and energy efficient cooling drives the emerging technology of magnetic refrigeration at room temperature. We fabricate a two phase mutiferroic La0.7Sr0.3MnO3/Pb(Mg1/3Nb2/3) O3-PbTiO3(001) via pulsed laser deposition for application in advanced near room-temperature refrigeration and miniature cooling devices. The key innovation rests on utilizing the magnetocaloric effect in zero applied magnetic fields. The magnetocaloric effect of the composite is activated purely by electric field. We utilize strain originating from stress which is voltage-induced via the inverse piezoelectric effect of PMN-PT. The strain is carried over into the adjacent LSMO thin film thus changing its magnetic order. The voltage-induced variation in magnetization leads to change in isothermal entropy when the experiment is carried out in contact with a thermostat and gives correspondingly rise to an adiabatic temperature change when heat exchange is suppressed. This project is supported by NSF through Nebraska MRSEC DMR-1420645.

  6. Current-oscillator correlation and Fano factor spectrum of quantum shuttle with finite bias voltage and temperature.

    Science.gov (United States)

    Lai, Wenxi; Cao, Yunshan; Ma, Zhongshui

    2012-05-01

    A general master equation is derived to describe an electromechanical single-dot transistor in the Coulomb blockade regime. In the equation, Fermi distribution functions in the two leads are taken into account, which allows one to study the system as a function of bias voltage and temperature of the leads. Furthermore, we treat the coherent interaction mechanism between electron tunneling events and the dynamics of excited vibrational modes. Stationary solutions of the equation are numerically calculated. We show that current through the oscillating island at low temperature appears to have step-like characteristics as a function of the bias voltage and the steps depend on the mean phonon number of the oscillator. At higher temperatures the current steps would disappear and this event is accompanied by the emergence of thermal noise of the charge transfer. When the system is mainly in the ground state, the zero frequency Fano factor of current manifests sub-Poissonian noise and when the system is partially driven into its excited states it exhibits super-Poissonian noise. The difference in the current noise would almost be removed for the situation in which the dissipation rate of the oscillator is much larger than the bare tunneling rates of electrons.

  7. AlGaN/GaN high electron mobility transistors as a voltage-tunable room temperature terahertz sources

    Science.gov (United States)

    El Fatimy, A.; Dyakonova, N.; Meziani, Y.; Otsuji, T.; Knap, W.; Vandenbrouk, S.; Madjour, K.; Théron, D.; Gaquiere, C.; Poisson, M. A.; Delage, S.; Prystawko, P.; Skierbiszewski, C.

    2010-01-01

    We report on room temperature terahertz generation by a submicron size AlGaN/GaN-based high electron mobility transistors. The emission peak is found to be tunable by the gate voltage between 0.75 and 2.1 THz. Radiation frequencies correspond to the lowest fundamental plasma mode in the gated region of the transistor channel. Emission appears at a certain drain bias in a thresholdlike manner. Observed emission is interpreted as a result of Dyakonov-Shur plasma wave instability in the gated two-dimensional electron gas.

  8. Ultra-Low Power High Temperature and Radiation Hard Complementary Metal-Oxide-Semiconductor (CMOS) Silicon-on-Insulator (SOI) Voltage Reference

    OpenAIRE

    El Hafed Boufouss; Francis, Laurent A.; Valeriya Kilchytska; Pierre Gérard; Pascal Simon; Denis Flandre

    2013-01-01

    This paper presents an ultra-low power CMOS voltage reference circuit which is robust under biomedical extreme conditions, such as high temperature and high total ionized dose (TID) radiation. To achieve such performances, the voltage reference is designed in a suitable 130 nm Silicon-on-Insulator (SOI) industrial technology and is optimized to work in the subthreshold regime of the transistors. The design simulations have been performed over the temperature range of -40–200 °C and for differ...

  9. A 5 V-to-3.3 V CMOS Linear Regulator with Three-Output Temperature-Independent Reference Voltages

    Directory of Open Access Journals (Sweden)

    San-Fu Wang

    2016-01-01

    Full Text Available This paper presents a 5 V-to-3.3 V linear regulator circuit, which uses 3.3 V CMOS transistors to replace the 5 V CMOS transistors. Thus, the complexity of the manufacturing semiconductor process can be improved. The proposed linear regulator is implemented by cascode architecture, which requires three different reference voltages as the bias voltages of its circuit. Thus, the three-output temperature-independent reference voltage circuit is proposed, which provides three accurate reference voltages simultaneously. The three-output temperature-independent reference voltages also can be used in other circuits of the chip. By using the proposed temperature-independent reference voltages, the proposed linear regulator can provide an accurate output voltage, and it is suitable for low cost, small size, and highly integrated system-on-chip (SoC applications. Moreover, the proposed linear regulator uses the cascode technique, which improves both the gain performance and the isolation performance. Therefore, the proposed linear regulator has a good performance in reference voltage to output voltage isolation. The voltage variation of the linear regulator is less than 2.153% in the temperature range of −40°C–120°C, and the power supply rejection ratio (PSRR is less than −42.8 dB at 60 Hz. The regulator can support 0~200 mA output current. The core area is less than 0.16 mm2.

  10. Dynamic in situ observation of voltage-driven repeatable magnetization reversal at room temperature

    Science.gov (United States)

    Gao, Ya; Hu, Jia-Mian; Nelson, C. T.; Yang, T. N.; Shen, Y.; Chen, L. Q.; Ramesh, R.; Nan, C. W.

    2016-03-01

    Purely voltage-driven, repeatable magnetization reversal provides a tantalizing potential for the development of spintronic devices with a minimum amount of power consumption. Substantial progress has been made in this subject especially on magnetic/ferroelectric heterostructures. Here, we report the in situ observation of such phenomenon in a NiFe thin film grown directly on a rhombohedral Pb(Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT) ferroelectric crystal. Under a cyclic voltage applied perpendicular to the PMN-PT without a magnetic field, the local magnetization of NiFe can be repetitively reversed through an out-of-plane excursion and then back into the plane. Using phase field simulations we interpret magnetization reversal as a synergistic effect of the metastable ferroelastic switching in the PMN-PT and an electrically rotatable local exchange bias field arising from the heterogeneously distributed NiO clusters at the interface.

  11. Characteristics of temperature rise in variable inductor employing magnetorheological fluid driven by a high-frequency pulsed voltage source

    Science.gov (United States)

    Lee, Ho-Young; Kang, In Man; Shon, Chae-Hwa; Lee, Se-Hee

    2015-05-01

    A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B-H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.

  12. Characteristics of temperature rise in variable inductor employing magnetorheological fluid driven by a high-frequency pulsed voltage source

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho-Young; Kang, In Man, E-mail: imkang@ee.knu.ac.kr [School of Electronics Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Shon, Chae-Hwa [Korea Electrotechnology Research Institute, Changwon 642-120 (Korea, Republic of); Lee, Se-Hee, E-mail: shlees@knu.ac.kr [Department of Electrical Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

    2015-05-07

    A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B–H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.

  13. Ultra-low power high temperature and radiation hard complementary metal-oxide-semiconductor (CMOS) silicon-on-insulator (SOI) voltage reference.

    Science.gov (United States)

    Boufouss, El Hafed; Francis, Laurent A; Kilchytska, Valeriya; Gérard, Pierre; Simon, Pascal; Flandre, Denis

    2013-12-13

    This paper presents an ultra-low power CMOS voltage reference circuit which is robust under biomedical extreme conditions, such as high temperature and high total ionized dose (TID) radiation. To achieve such performances, the voltage reference is designed in a suitable 130 nm Silicon-on-Insulator (SOI) industrial technology and is optimized to work in the subthreshold regime of the transistors. The design simulations have been performed over the temperature range of -40-200 °C and for different process corners. Robustness to radiation was simulated using custom model parameters including TID effects, such as mobilities and threshold voltages degradation. The proposed circuit has been tested up to high total radiation dose, i.e., 1 Mrad (Si) performed at three different temperatures (room temperature, 100 °C and 200 °C). The maximum drift of the reference voltage V(REF) depends on the considered temperature and on radiation dose; however, it remains lower than 10% of the mean value of 1.5 V. The typical power dissipation at 2.5 V supply voltage is about 20 μW at room temperature and only 75 μW at a high temperature of 200 °C. To understand the effects caused by the combination of high total ionizing dose and temperature on such voltage reference, the threshold voltages of the used SOI MOSFETs were extracted under different conditions. The evolution of V(REF) and power consumption with temperature and radiation dose can then be explained in terms of the different balance between fixed oxide charge and interface states build-up. The total occupied area including pad-ring is less than 0.09 mm2.

  14. Ultra-Low Power High Temperature and Radiation Hard Complementary Metal-Oxide-Semiconductor (CMOS Silicon-on-Insulator (SOI Voltage Reference

    Directory of Open Access Journals (Sweden)

    El Hafed Boufouss

    2013-12-01

    Full Text Available This paper presents an ultra-low power CMOS voltage reference circuit which is robust under biomedical extreme conditions, such as high temperature and high total ionized dose (TID radiation. To achieve such performances, the voltage reference is designed in a suitable 130 nm Silicon-on-Insulator (SOI industrial technology and is optimized to work in the subthreshold regime of the transistors. The design simulations have been performed over the temperature range of -40–200 °C and for different process corners. Robustness to radiation was simulated using custom model parameters including TID effects, such as mobilities and threshold voltages degradation. The proposed circuit has been tested up to high total radiation dose, i.e., 1 Mrad (Si performed at three different temperatures (room temperature, 100 °C and 200 °C. The maximum drift of the reference voltage VREF depends on the considered temperature and on radiation dose; however, it remains lower than 10% of the mean value of 1.5 V. The typical power dissipation at 2.5 V supply voltage is about 20 μW at room temperature and only 75 μ W at a high temperature of 200 °C. To understand the effects caused by the combination of high total ionizing dose and temperature on such voltage reference, the threshold voltages of the used SOI MOSFETs were extracted under different conditions. The evolution of VREF and power consumption with temperature and radiation dose can then be explained in terms of the different balance between fixed oxide charge and interface states build-up. The total occupied area including pad-ring is less than 0.09 mm2.

  15. The cytoplasmic coiled-coil mediates cooperative gating temperature sensitivity in the voltage-gated H(+) channel Hv1.

    Science.gov (United States)

    Fujiwara, Yuichiro; Kurokawa, Tatsuki; Takeshita, Kohei; Kobayashi, Megumi; Okochi, Yoshifumi; Nakagawa, Atsushi; Okamura, Yasushi

    2012-05-08

    Hv1/VSOP is a dimeric voltage-gated H(+) channel in which the gating of one subunit is reportedly coupled to that of the other subunit within the dimer. The molecular basis for dimer formation and intersubunit coupling, however, remains unknown. Here we show that the carboxy terminus ends downstream of the S4 voltage-sensor helix twist in a dimer coiled-coil architecture, which mediates cooperative gating. We also show that the temperature-dependent activation of H(+) current through Hv1/VSOP is regulated by thermostability of the coiled-coil domain, and that this regulation is altered by mutation of the linker between S4 and the coiled-coil. Cooperative gating within the dimer is also dependent on the linker structure, which circular dichroism spectrum analysis suggests is α-helical. Our results indicate that the cytoplasmic coiled-coil strands form continuous α-helices with S4 and mediate cooperative gating to adjust the range of temperatures over which Hv1/VSOP operates.

  16. Thermoacoustic and thermoreflectance imaging of biased integrated circuits: Voltage and temperature maps

    Science.gov (United States)

    Hernández-Rosales, E.; Cedeño, E.; Hernandez-Wong, J.; Rojas-Trigos, J. B.; Marin, E.; Gandra, F. C. G.; Mansanares, A. M.

    2016-07-01

    In this work a combined thermoacoustic and thermoreflectance set-up was designed for imaging biased microelectronic circuits. In particular, it was used with polycrystalline silicon resistive tracks grown on a monocrystalline Si substrate mounted on a test chip. Thermoreflectance images, obtained by scanning a probe laser beam on the sample surface, clearly show the regions periodically heated by Joule effect, which are associated to the electric current distribution in the circuit. The thermoacoustic signal, detected by a pyroelectric/piezoelectric sensor beneath the chip, also discloses the Joule contribution of the whole sample. However, additional information emerges when a non-modulated laser beam is focused on the sample surface in a raster scan mode allowing imaging of the sample. The distribution of this supplementary signal is related to the voltage distribution along the circuit.

  17. Thermoacoustic and thermoreflectance imaging of biased integrated circuits: Voltage and temperature maps

    Energy Technology Data Exchange (ETDEWEB)

    Hernández-Rosales, E.; Cedeño, E. [Gleb Wataghin Physics Institute, University of Campinas - Unicamp, 13083-859 Campinas, SP (Brazil); Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Legaria 694, Colonia Irrigación, CP 11500, México, DF (Mexico); Hernandez-Wong, J. [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Legaria 694, Colonia Irrigación, CP 11500, México, DF (Mexico); CONACYT, México, DF, México (Mexico); Rojas-Trigos, J. B.; Marin, E. [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Legaria 694, Colonia Irrigación, CP 11500, México, DF (Mexico); Gandra, F. C. G.; Mansanares, A. M., E-mail: manoel@ifi.unicamp.br [Gleb Wataghin Physics Institute, University of Campinas - Unicamp, 13083-859 Campinas, SP (Brazil)

    2016-07-25

    In this work a combined thermoacoustic and thermoreflectance set-up was designed for imaging biased microelectronic circuits. In particular, it was used with polycrystalline silicon resistive tracks grown on a monocrystalline Si substrate mounted on a test chip. Thermoreflectance images, obtained by scanning a probe laser beam on the sample surface, clearly show the regions periodically heated by Joule effect, which are associated to the electric current distribution in the circuit. The thermoacoustic signal, detected by a pyroelectric/piezoelectric sensor beneath the chip, also discloses the Joule contribution of the whole sample. However, additional information emerges when a non-modulated laser beam is focused on the sample surface in a raster scan mode allowing imaging of the sample. The distribution of this supplementary signal is related to the voltage distribution along the circuit.

  18. Effect of Light Intensity and Temperature on the Current Voltage Characteristics of Al/ SY/ p- Si Organic-Inorganic Heterojunction

    Science.gov (United States)

    Imer, Arife Gencer; Ocak, Yusuf Selim

    2016-10-01

    An organic-inorganic contact was fabricated by forming a thin film of sunset yellow dye ( SY) on a p- Si wafer. The device showed a good rectification property, and the sunset yellow thin film modified the barrier height (Φb) of Al/ p- Si contact by influencing the space charge region. The heterojunction had a strong response to the different illumination intensities and showed that it can be suitable for photodiode applications. The I- V measurements of the device were also applied in the temperature range of 100-500 K. It was seen that characteristic parameters of the device were strongly dependent upon temperature. While the value of Φb increased, the ideality factor ( n) decreased with the increase in temperature. This variation was attributed to spatial inhomogeneity at the interface. The Norde function was used to determine the temperature-dependent series resistance and Φb values, and there was a good agreement with that of ln I- V data. The values of the Richardson constant ( A*) and mean Φb were determined as 29.47 Acm-2 K-2 by means of a modified activation energy plot, matching with a theoretical one, and 1.032 eV, respectively. Therefore, it was stated that the current voltage characteristic with the temperature can be explained by thermionic emission theory with Gaussian distribution of the Φb at the interface.

  19. Characterization and Modeling of Superconducting Josephson Junction Arrays at Low Voltage and Liquid Helium Temperatures

    Science.gov (United States)

    2016-09-01

    Applied Research Under authority of A. D. Ramirez , Head Advanced Systems and Applied Sciences Division iii EXECUTIVE SUMMARY This...to the characteristics and extract the non -ideality. These capabilities and calibration results will assist in the characterization of advanced...superconducting cryogenic temperatures. At this temperature, the I-V curve is linear . This linearity occurs because when the Josephson junctions are not in

  20. Breakdown voltage of metal-oxide resistors in liquid argon

    CERN Document Server

    Bagby, L F; James, C C; Jones, B J P; Jostlein, H; Lockwitz, S; Naples, D; Raaf, J L; Rameika, R; Schukraft, A; Strauss, T; Weber, M S; Wolbers, S A

    2014-01-01

    We characterized a sample of metal-oxide resistors and measured their breakdown voltage in liquid argon by applying high voltage (HV) pulses over a 3 second period to simulate the electric breakdown in a HV-divider chain. All resistors had higher breakdown voltages in liquid argon than their vendor ratings in air at room temperature. Failure modes range from full destruction to coating damage. In cases where breakdown was not catastrophic, subsequent breakdown voltages were lower in subsequent measuring runs. One resistor type withstands 131\\,kV pulses, the limit of the test setup.

  1. High-temperature performance of MoS{sub 2} thin-film transistors: Direct current and pulse current-voltage characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, C.; Samnakay, R.; Balandin, A. A., E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory (NDL), Department of Electrical Engineering, Bourns College of Engineering, University of California—Riverside, Riverside, California 92521 (United States); Phonon Optimized Engineered Materials (POEM) Center, Materials Science and Engineering Program, University of California—Riverside, Riverside, California 92521 (United States); Rumyantsev, S. L. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Shur, M. S. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-02-14

    We report on fabrication of MoS{sub 2} thin-film transistors (TFTs) and experimental investigations of their high-temperature current-voltage characteristics. The measurements show that MoS{sub 2} devices remain functional to temperatures of at least as high as 500 K. The temperature increase results in decreased threshold voltage and mobility. The comparison of the direct current (DC) and pulse measurements shows that the direct current sub-linear and super-linear output characteristics of MoS{sub 2} thin-films devices result from the Joule heating and the interplay of the threshold voltage and mobility temperature dependences. At temperatures above 450 K, a kink in the drain current occurs at zero gate voltage irrespective of the threshold voltage value. This intriguing phenomenon, referred to as a “memory step,” was attributed to the slow relaxation processes in thin films similar to those in graphene and electron glasses. The fabricated MoS{sub 2} thin-film transistors demonstrated stable operation after two months of aging. The obtained results suggest new applications for MoS{sub 2} thin-film transistors in extreme-temperature electronics and sensors.

  2. Temperature influence and reset voltage study of bipolar resistive switching behaviour in ZrO2 thin films

    Indian Academy of Sciences (India)

    Ying Li; Gaoyang Zhao; Jian Su; Erfeng Shen; Yang Ren

    2014-05-01

    We have fabricated ZrO2 thin films by sol–gel deposition and annealed them at 300, 500 and 700 °C. Reproducible - curves can be obtained for the device Cu/ZrO2/ATO which is measured at room temperature (300 K). During the RESET operation, L and H values can be controlled by the RESET voltage. Moreover, the Cu/ZrO2/ATO device which the ZrO2 thin film annealed at 300 °C can be measured as resistive switching sweeps at 200, 100 and 50 K. It was found that the ratio of off/on reduced when the measured temperature decreased. When the - measurement temperature decreases, on decreases obviously which is typical for electronic transportation in a Cu metal. It is indicated that the Cu metallic conduction filament has been formed in the ZrO2 films. Besides, the microstructure by high resolution transmission electrical microscopy (HRTEM) was also investigated.

  3. Voltage gating by molecular subunits of Na+ and K+ ion channels: higher-dimensional cubic kinetics, rate constants, and temperature.

    Science.gov (United States)

    Fohlmeister, Jürgen F

    2015-06-01

    The structural similarity between the primary molecules of voltage-gated Na and K channels (alpha subunits) and activation gating in the Hodgkin-Huxley model is brought into full agreement by increasing the model's sodium kinetics to fourth order (m(3) → m(4)). Both structures then virtually imply activation gating by four independent subprocesses acting in parallel. The kinetics coalesce in four-dimensional (4D) cubic diagrams (16 states, 32 reversible transitions) that show the structure to be highly failure resistant against significant partial loss of gating function. Rate constants, as fitted in phase plot data of retinal ganglion cell excitation, reflect the molecular nature of the gating transitions. Additional dimensions (6D cubic diagrams) accommodate kinetically coupled sodium inactivation and gating processes associated with beta subunits. The gating transitions of coupled sodium inactivation appear to be thermodynamically irreversible; response to dielectric surface charges (capacitive displacement) provides a potential energy source for those transitions and yields highly energy-efficient excitation. A comparison of temperature responses of the squid giant axon (apparently Arrhenius) and mammalian channel gating yields kinetic Q10 = 2.2 for alpha unit gating, whose transitions are rate-limiting at mammalian temperatures; beta unit kinetic Q10 = 14 reproduces the observed non-Arrhenius deviation of mammalian gating at low temperatures; the Q10 of sodium inactivation gating matches the rate-limiting component of activation gating at all temperatures. The model kinetics reproduce the physiologically large frequency range for repetitive firing in ganglion cells and the physiologically observed strong temperature dependence of recovery from inactivation. Copyright © 2015 the American Physiological Society.

  4. SOI-Based High-Voltage, High-Temperature Integrated Circuit Gate Driver for SiC-Based Power FETs

    Energy Technology Data Exchange (ETDEWEB)

    Huque, Mohammad A [ORNL; Tolbert, Leon M [ORNL; Blalock, Benjamin [University of Tennessee, Knoxville (UTK); Islam, Syed K [University of Tennessee, Knoxville (UTK)

    2010-01-01

    Silicon carbide (SiC)-based field effect transistors (FETs) are gaining popularity as switching elements in power electronic circuits designed for high-temperature environments like hybrid electric vehicle, aircraft, well logging, geothermal power generation etc. Like any other power switches, SiC-based power devices also need gate driver circuits to interface them with the logic units. The placement of the gate driver circuit next to the power switch is optimal for minimizing system complexity. Successful operation of the gate driver circuit in a harsh environment, especially with minimal or no heat sink and without liquid cooling, can increase the power-to-volume ratio as well as the power-to-weight ratio for power conversion modules such as a DC-DC converter, inverter etc. A silicon-on-insulator (SOI)-based high-voltage, high-temperature integrated circuit (IC) gate driver for SiC power FETs has been designed and fabricated using a commercially available 0.8-m, 2-poly and 3-metal bipolar-complementary metal oxide semiconductor (CMOS)-double diffused metal oxide semiconductor (DMOS) process. The prototype circuit-s maximum gate drive supply can be 40-V with peak 2.3-A sourcing/sinking current driving capability. Owing to the wide driving range, this gate driver IC can be used to drive a wide variety of SiC FET switches (both normally OFF metal oxide semiconductor field effect transistor (MOSFET) and normally ON junction field effect transistor (JFET)). The switching frequency is 20-kHz and the duty cycle can be varied from 0 to 100-. The circuit has been successfully tested with SiC power MOSFETs and JFETs without any heat sink and cooling mechanism. During these tests, SiC switches were kept at room temperature and ambient temperature of the driver circuit was increased to 200-C. The circuit underwent numerous temperature cycles with negligible performance degradation.

  5. Continental Divide Trail

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This shapefile was created to show the proximity of the Continental Divide to the Continental Divide National Scenic Trail in New Mexico. This work was done as part...

  6. The current-voltage and noise properties of high temperature superconductor SNS and grain boundary junctions

    CERN Document Server

    McGordon, A

    1999-01-01

    transport that was dominated by the interlayer material, but supercurrent transport that could be due to pinhole shorts. In addition, both geometries, especially the sandwich junction, showed large amounts of normal state noise making these junctions unsuitable for device applications. The effect of shining laser light onto a junction was investigated. The effects on the I-V characteristic were unobservable with the experimental resolution available. The effect of the light on the critical current noise of the junction was to reduce the noise peak slightly when compared to the unilluminated case- the reduction was of the order of 10%, comparable with experimental resolution. The study of the noise from Josephson Junctions is an intense field of research. Despite this, no clear picture of the current transport in these devices has emerged. Without the detailed understanding of the mechanisms of current transport in High Temperature Superconductor junctions, the design of superconducting electronics will not mo...

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

    Science.gov (United States)

    He, Yandong; Zhang, Ganggang; Zhang, Xing

    2014-01-01

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

  8. Development of the Composite High Voltage Optical Fiber Temperature Measurement Cable%高压光纤复合测温电缆的研制

    Institute of Scientific and Technical Information of China (English)

    金金元

    2012-01-01

    In order to use optical fiber distributed temperature monitoring system to on-line monitor the temperature of the cable in operation; a composite high voltage fiber optic temperature measuring cable is developed independently. The structure design, the production process of building in of the fibers, and the performance testing of the composite high voltage optical fiber temperature measuring cable are described in detail.%为利用光纤分布式温度监测系统对运行电缆的温度进行实时在线监测,自主开发了高压光纤复合测温电缆。对高压光纤复合测温电缆结构设计、光纤内置等制造过程和性能检测进行了较为详细的阐述。

  9. International Divider Walls

    NARCIS (Netherlands)

    Kruis, A.; Sneller, A.C.W.(L.)

    2013-01-01

    The subject of this teaching case is the Enterprise Resource Planning (ERP) system implementation at International Divider Walls, the world market leader in design, production, and sales of divider walls. The implementation in one of the divisions of this multinational company had been successful, a

  10. International Divider Walls

    NARCIS (Netherlands)

    Kruis, A.; Sneller, A.C.W.(L.)

    2013-01-01

    The subject of this teaching case is the Enterprise Resource Planning (ERP) system implementation at International Divider Walls, the world market leader in design, production, and sales of divider walls. The implementation in one of the divisions of this multinational company had been successful,

  11. Programming Arduino to Control Bias Voltages to Temperature-Depedndent Gamma-ray Detectors aboard TRYAD Mission

    Science.gov (United States)

    Stevons, C. E.; Jenke, P.; Briggs, M. S.

    2016-12-01

    Terrestrial Gamma-ray Flashes (TGFs) are sub-millisecond gamma-ray flashes that are correlated with lightning have been observed with numerous satellites since their discovery in the early 1990s. Although substantial research has been conducted on TGFs, puzzling questions regarding their origin are still left unanswered. Consequently, the Terrestrial RaYs Analysis and Detection (TRYAD) mission is designed to solve many issues about TGFs by measuring the beam profile and orientation of TGFs in low Earth orbit. This project consists of sending two CubeSats into low-Earth orbit where they will independently sample TGF beams. Both of the TRYAD CubeSats will contain a gamma-ray detector composed of lead doped plastic scintillator coupled to silicon photomultiplier (SiPM) arrays. The gain readings of the SiPMs vary with temperature and the bias voltage must be corrected to compensate. Using an Arduino micro-controller, circuitry and software was developed to control the gain in response to the resistance of a thermistor. I will present the difficulties involved with this project along with our solutions.

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

    Science.gov (United States)

    Hashemi, Adeleh; Bahari, Ali; Ghasemi, Shahram

    2017-09-01

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

  13. Bridging the Digital Divide

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    2002-01-01

    The article concerns the digital divide, meaning the social inequity in the access and the opportunities for gaining competencies with ICT (information and communication technologies). Problematic issues are highlighted in relation to experiences during visits to several Computer Clubhouses...

  14. The Open Access Divide

    National Research Council Canada - National Science Library

    Jingfeng Xia

    2013-01-01

      This paper is an attempt to review various aspects of the open access divide regarding the difference between those academics who support free sharing of data and scholarly output and those academics who do...

  15. 高压带电体温度检测装置%Temperature Detection Device of High-voltage Electrified Body

    Institute of Scientific and Technical Information of China (English)

    谭光韧; 宋峰; 吴建华

    2012-01-01

    In order to solve problems of electrical insulation and low precision existed in traditional temperature detection methods of high-voltage electrified body, the paper introduced a design scheme of a novel temperature detection device of high-voltage electrified body. The device collects temperature signals by use of temperature sensor of traditional contacting temperature detection methods, and uses a method of controlled current source and induced power source to supply power. Each induced power source connects controlled current source through high-voltage wire, induced power sources has no connection with each other at different measuring point, and fiber is as transmission medium of temperature signals, so as to realize electrical insulation. The experimental result showed that the device has stable voltage of induced power source, high precision and strong anti-interference ability.%针对传统高压带电体测温方法存在的难以实现电气绝缘、精度低等问题,介绍了一种新型高压带电体温度检测装置的设计方案.该装置采用传统接触式测温方式下的温度传感器采集温度信号,采用可调电流源+感生电源方式实现供电,各感生电源与可调电流源通过高压线连接,不同测温点的感生电源之间没有电气连接,且采用光纤传输温度信号,从而很好地实现了电气绝缘.实验结果表明,该装置的感生电源电压稳定,测温精度高,抗干扰能力强.

  16. The Open Access Divide

    Directory of Open Access Journals (Sweden)

    Jingfeng Xia

    2013-10-01

    Full Text Available This paper is an attempt to review various aspects of the open access divide regarding the difference between those academics who support free sharing of data and scholarly output and those academics who do not. It provides a structured description by adopting the Ws doctrines emphasizing such questions as who, what, when, where and why for information-gathering. Using measurable variables to define a common expression of the open access divide, this study collects aggregated data from existing open access as well as non-open access publications including journal articles and extensive reports. The definition of the open access divide is integrated into the discussion of scholarship on a larger scale.

  17. Breakdown voltage of metal-oxide resistors in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Bagby, L. F. [Fermilab; Gollapinni, S. [Kansas State U.; James, C. C. [Fermilab; Jones, B. J.P. [MIT; Jostlein, H. [Fermilab; Lockwitz, S. [Fermilab; Naples, D. [Pittsburgh U.; Raaf, J. L. [Fermilab; Rameika, R. [Fermilab; Schukraft, A. [Fermilab; Strauss, T. [Bern U., LHEP; Weber, M. S. [Bern U., LHEP; Wolbers, S. A. [Fermilab

    2014-11-07

    We characterized a sample of metal-oxide resistors and measured their breakdown voltage in liquid argon by applying high voltage (HV) pulses over a 3 second period. This test mimics the situation in a HV-divider chain when a breakdown occurs and the voltage across resistors rapidly rise from the static value to much higher values. All resistors had higher breakdown voltages in liquid argon than their vendor ratings in air at room temperature. Failure modes range from full destruction to coating damage. In cases where breakdown was not catastrophic, subsequent breakdown voltages were lower in subsequent measuring runs. One resistor type withstands 131 kV pulses, the limit of the test setup.

  18. A Flexible Three-in-One Microsensor for Real-Time Monitoring of Internal Temperature, Voltage and Current of Lithium Batteries

    Directory of Open Access Journals (Sweden)

    Chi-Yuan Lee

    2015-05-01

    Full Text Available Lithium batteries are widely used in notebook computers, mobile phones, 3C electronic products, and electric vehicles. However, under a high charge/discharge rate, the internal temperature of lithium battery may rise sharply, thus causing safety problems. On the other hand, when the lithium battery is overcharged, the voltage and current may be affected, resulting in battery instability. This study applies the micro-electro-mechanical systems (MEMS technology on a flexible substrate, and develops a flexible three-in-one microsensor that can withstand the internal harsh environment of a lithium battery and instantly measure the internal temperature, voltage and current of the battery. Then, the internal information can be fed back to the outside in advance for the purpose of safety management without damaging the lithium battery structure. The proposed flexible three-in-one microsensor should prove helpful for the improvement of lithium battery design or material development in the future.

  19. A dividing issue

    DEFF Research Database (Denmark)

    Gamborg, Christian; Jensen, Frank Søndergaard; Sandøe, Peter

    2016-01-01

    . While there was broad agreement across all three groups that recreational hunting of naturally occurring “surplus” wildlife is acceptable, the release of farm-reared game birds for shooting was a dividing issue, both within the groups and between them. The majority of participants (51%) in the survey...

  20. Divide and Pacify

    DEFF Research Database (Denmark)

    Vanhuysse, Pieter

    by pointing to deeper political motives and wider sociological consequences. Divide and Pacify was nominated for the American Sociological Association's Award for Distinguished Contribution to Scholarship 2006, Section on Political Sociology. Praise and reviews: "Pieter Vanhuysse…is a political scientist...... across many settings in which democratic governments face the task of implementing costly reforms in complex and uncertain policy environments." –János Kornai, Harvard University "Divide and Pacify contains a provocative thesis about the manner in which political strategy was used to consolidate...... policy." - Kenneth Shepsle, Professor, Harvard University and Fellow, American Academy of Sciences "In post-communist Europe, international advice—for example from the International Monetary Fund and the World Bank—to reforming governments focused heavily on economic policy. The political imperative...

  1. Investigation of temperature dependent threshold voltage variation of Gd2O3/AlGaN/GaN metal-oxide-semiconductor heterostructure

    Directory of Open Access Journals (Sweden)

    Atanu Das

    2012-09-01

    Full Text Available Temperature dependent threshold voltage (Vth variation of GaN/AlGaN/Gd2O3/Ni-Au structure is investigated by capacitance-voltage measurement with temperature varying from 25°C to 150°C. The Vth of the Schottky device without oxide layer is slightly changed with respect to temperature. However, variation of Vth is observed for both as-deposited and annealed device owing to electron capture by the interface traps or bulk traps. The Vth shifts of 0.4V and 3.2V are obtained for as-deposited and annealed device respectively. For annealed device, electron capture process is not only restricted in the interface region but also extended into the crystalline Gd2O3 layer through Frenkel-Poole emission and hooping conduction, resulting in a larger Vth shift. The calculated trap density for as-deposited and annealed device is 3.28×1011∼1.12×1011 eV−1cm−2 and 1.74×1012∼7.33×1011 eV−1cm−2 respectively in measured temperature range. These results indicate that elevated temperature measurement is necessary to characterize GaN/AlGaN heterostructure based devices with oxide as gate dielectric.

  2. Bridging the Digital Divide

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    2002-01-01

    The article concerns the digital divide, meaning the social inequity in the access and the opportunities for gaining competencies with ICT (information and communication technologies). Problematic issues are highlighted in relation to experiences during visits to several Computer Clubhouses......, a network of multimedia workshops for youth in the USA. There are references to the learning philosophy Constructionism, which originates from MIT Media Lab and is the basis for the Computer Clubhouse project. Abstract : The consortium for Math and Science at Learning Lab Denmark and the Ministry...... of significant European initiatives promoting the recruitment and quality of the science and technology educations....

  3. CROSSING THE GREAT DIVIDE

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The safety and quality standards divide is the most severe challenge facing China’s toy industry China was blamed a spate of toy recalls this year.Overseas customers and press pointed the finger at China’s toy makers who had manu- factured toys according to their con- tracts.It was later found that most of the toy problems came from design faults of brand holders,not from Chinese manufacturers. To Wei Chuangzhong,Vice Minister of the General Administration of Quality Supervision,Inspection and Quarantine (AQSIQ),the cavalcade of negative press coverage overseas has been unfair and bad for China’s manufacturers.

  4. Monitoring the Digital Divide

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, Les

    2003-05-28

    It is increasingly important to support the large numbers of scientists working in remote areas and having low bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste, a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent ''Recommendations of Trieste'' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work.

  5. Influence of temperature on the ionization coefficient and ignition voltage of the Townsend discharge in an argon-mercury vapor mixture

    Science.gov (United States)

    Bondarenko, G. G.; Fisher, M. R.; Kristya, V. I.

    2017-02-01

    The kinetics of main types of charged and excited particles present in a low-current discharge in an argon-mercury vapor mixture used in gas-discharge illuminating lamps has been investigated in a wide interval of the reduced electric field strength and temperature. Mechanisms behind the production and loss of ions and metastable atoms have been discovered, and the temperature dependences of their contributions to maintaining their balance have been determined. It has been shown that, when the discharge is initiated in the lamp and the mercury content in the mixture is low, the ionization coefficient exceeds that in pure argon, which is almost exclusively due to the Penning reaction. The influence of this reaction grows with a reduction of the electric field strength in the interelectrode gap. The dependences of the discharge ignition voltage on the interelectrode gap (Paschen curves) for different temperatures of the mixture have been calculated, and the nonmonotonicity of the temperature dependence of the ignition voltage has been explained.

  6. A Low Temperature Coefficient Bandgap Voltage Reference Source%一种低温度系数带隙基准电压源

    Institute of Scientific and Technical Information of China (English)

    孙大开; 李斌桥; 徐江涛; 李晓晨

    2012-01-01

    描述了一个具有高电源抑制比和低温度系数的带隙基准电压源电路.基于1阶零温度系数点可调节的结构,通过对不同零温度系数点带隙电压的转换实现低温度系数,并采用了电源波动抑制电路.采用SMIC 0.18 μm CMOS工艺,经过Cadence Spectre仿真验证,在-20℃~100℃温度范围内,电压变化范围小于0.5 mV,温度系数不超过7×1006/℃.低频下的电源抑制比为-107 dB,在10 kHz下,电源抑制比可达到-90 dB.整个电路在供电电压大于2.3V时可以实现正常启动,在3.3V电源供电下,电路的功耗约为1.05 mW.%A bandgap voltage reference source with high PSRR and low temperature coefficient was presented, in which low temperature coefficient was achieved by switching between bandgap voltages at different zero-temperature coefficient points, and a power noise rejection circuit was designed. The circuit was simulated with Spectre of Cadence based on SMIC's 0. 18 祄 CMOS process. Simulation results showed that the circuit had a voltage swing less the 0. 5 mV, a max temperature coefficient of 7X 10-6/?in the temperature range from -20 'C to 120 ?, a PSSR of -107 dB and -90 dB at DC power supply and 10 kHz of AC frequency, respectively. The bandgap reference source could start properly at a supply voltage higher than 2. 3 V, and it dissipated 1. 05 mW of power from a 3. 3 V supply.

  7. Why do bacteria divide?

    Directory of Open Access Journals (Sweden)

    Vic eNorris

    2015-04-01

    Full Text Available The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life – Life as independent of its constituents – is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass – its cellular connectivity – would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity – Life on the Scales of Equilibria – is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium and non-equilibrium cellular compounds and structures appropriate for survival and growth, respectively, alias `hyperstructures'. The corollary is that the cell senses both the quantity of equilibrium material and the intensity of use of non-equilibrium material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence – Competitive Coherence – is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell’s contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics

  8. Why do bacteria divide?

    Science.gov (United States)

    Norris, Vic

    2015-01-01

    The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life - Life as independent of its constituents - is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass - its cellular connectivity - would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity - Life on the Scales of Equilibria - is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium (E) and non-equilibrium (NE) cellular compounds and structures appropriate for survival and growth, respectively, alias 'hyperstructures.' The corollary is that the cell senses both the quantity of E material and the intensity of use of NE material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence - Competitive Coherence - is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell's contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics to the cell cycle itself.

  9. A study on the dependency of the open-circuit voltage on temperature and actual aging state of lithium-ion batteries

    Science.gov (United States)

    Farmann, Alexander; Sauer, Dirk Uwe

    2017-04-01

    The knowledge of nonlinear monotonic correlation between State-of-Charge (SoC) and open-circuit voltage (OCV) is necessary for an accurate battery state estimation in battery management systems. Among the main factors influencing the OCV behavior of lithium-ion batteries (LIBs) are aging, temperature and previous history of the battery. In order to develop an accurate OCV-based SoC estimator, it is necessary that the OCV behavior of the LIBs is sufficiently investigated and understood. In this study, the impact of the mentioned factors on OCV of LIBs at different aging states using various active materials (C/NMC, C/LFP, LTO/NMC) is investigated over a wide temperature range (from -20 °C to +45 °C) comprehensively. It is shown that temperature and aging of the battery influence the battery's relaxation behavior significantly where a linear dependence between the required relaxation time and the temperature can be assumed. Moreover, the required relaxation time increases with decreasing SoC and temperature. Furthermore, we state that for individual LIB, the OCV and the OCV hysteresis change over the battery lifetime. Based on the obtained results a simplified OCV model considering temperature correction term and aging of the battery is proposed.

  10. Analysis of temperature-dependant current–voltage characteristics and extraction of series resistance in Pd/ZnO Schottky barrier diodes

    Energy Technology Data Exchange (ETDEWEB)

    Mayimele, M A, E-mail: meehleketo@gmail.com; Rensburg, J P van. Janse; Auret, F D; Diale, M

    2016-01-01

    We report on the analysis of current voltage (I–V) measurements performed on Pd/ZnO Schottky barrier diodes (SBDs) in the 80–320 K temperature range. Assuming thermionic emission (TE) theory, the forward bias I–V characteristics were analysed to extract Pd/ZnO Schottky diode parameters. Comparing Cheung’s method in the extraction of the series resistance with Ohm’s law, it was observed that at lower temperatures (T<180 K) the series resistance decreased with increasing temperature, the absolute minimum was reached near 180 K and increases linearly with temperature at high temperatures (T>200 K). The barrier height and the ideality factor decreased and increased, respectively, with decrease in temperature, attributed to the existence of barrier height inhomogeneity. Such inhomogeneity was explained based on TE with the assumption of Gaussian distribution of barrier heights with a mean barrier height of 0.99 eV and a standard deviation of 0.02 eV. A mean barrier height of 0.11 eV and Richardson constant value of 37 A cm{sup −2} K{sup −2} were determined from the modified Richardson plot that considers the Gaussian distribution of barrier heights.

  11. An improved fully integrated, high-speed, dual-modulus divider

    Science.gov (United States)

    Zheng, Sun; Yong, Xu; Guangyan, Ma; Hui, Shi; Fei, Zhao; Ying, Lin

    2014-11-01

    A fully integrated 2n/2n+1 dual-modulus divider in GHz frequency range is presented. The improved structure can make all separated logic gates embed into correlative D flip—flops completely. In this way, the complex logic functions can be performed with a minimum number of devices and with maximum speed, so that lower power consumption and faster speed are obtained. In addition, the low-voltage bandgap reference needed by the frequency divider is specifically designed to provide a 1.0 V output. According to the design demand, the circuit is fabricated in 0.18 μm standard CMOS process, and the measured results show that its operating frequency range is 1.1-2.5 GHz. The dual-modulus divider dissipates 1.1 mA from a 1.8 V power supply. The temperature coefficient of the reference voltage circuit is 8.3 ppm/°C when the temperature varies from -40 to +125 °C. By comparison, the dual-modulus divide designed in this paper can possess better performance and flexibility.

  12. An improved fully integrated, high-speed, dual-modulus divider

    Institute of Scientific and Technical Information of China (English)

    Sun Zheng; Xu Yong; Ma Guangyan; Shi Hui; Zhao Fei; Lin Ying

    2014-01-01

    A fully integrated 2n/2n+l dual-modulus divider in GHz frequency range is presented.The improved structure can make all separated logic gates embed into correlative D flip-flops completely.In this way,the complex logic functions can be performed with a minimum number of devices and with maximum speed,so that lower power consumption and faster speed are obtained.In addition,the low-voltage bandgap reference needed by the frequency divider is specifically designed to provide a 1.0 V output.According to the design demand,the circuit is fabricated in 0.18μm standard CMOS process,and the measured results show that its operating frequency range is 1.1-2.5 GHz.The dual-modulus divider dissipates 1.1 mA from a 1.8 V power supply.The temperature coefficient of the reference voltage circuit is 8.3 ppm/℃ when the temperature varies from-40 to + 125 ℃.By comparison,the dual-modulus divide designed in this paper can possess better performance and flexibility.

  13. Relationship between Work Function of Hole Collection Electrode and Temperature Dependence of Open-Circuit Voltage in Multilayered Organic Solar Cells

    Science.gov (United States)

    Itoh, Eiji; Shirotori, Toshiki

    2012-02-01

    We have investigated the photovoltaic properties of multilayered organic photovoltaic devices consisting of indium tin oxide (ITO)/(NiO)/donor/C60/bathocuproine (BCP)/Al structures. Open circuit voltage (VOC) increases with the decrease in temperature between 40 and 350 K. The VOC was, however, pinned at approximately 0.6 V for the device without NiO, probably owing to the insufficient work-function difference between ITO and Al electrodes. The hole injection was also markedly suppressed at the ITO/donor interface in the device with large IP donor materials without the buffer layer and abnormal S-shaped current density-voltage (J-V) characteristics were observed. On the other hand, the value of VOC increases with the increase in ionization potential (IP) of donor materials in the device with NiO buffer layers owing to the enhanced work-function difference of about 1 eV, and the S-shaped curves disappeared at the high temperatures above 200 K. The VOC is further improved to nearly 1.2 V by the UV-ozone treatment of the NiO surface. We have therefore concluded that the increment of work function of the anode caused by the insertion of an oxide buffer layer and the surface treatment of the electrode by UV-ozone treatment are essentially important for the improvement of VOC and charge transport/injection properties in the multilayered organic solar cell applications.

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

    Science.gov (United States)

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

    2015-07-15

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

  15. Influence of deposition temperature and bias voltage on the crystalline phase of Er{sub 2}O{sub 3} thin films deposited by filtered cathodic arc

    Energy Technology Data Exchange (ETDEWEB)

    Adelhelm, Christoph, E-mail: christoph.adelhelm@ipp.mpg.de [Max-Planck-Institut fuer Plasmaphysik, Materials Research, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany); Pickert, Thomas [Max-Planck-Institut fuer Plasmaphysik, Materials Research, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany); Koch, Freimut, E-mail: freimut.koch@ipp.mpg.de [Max-Planck-Institut fuer Plasmaphysik, Materials Research, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany); Balden, Martin; Jahn, Stephan [Max-Planck-Institut fuer Plasmaphysik, Materials Research, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany); Rinke, Monika [Forschungszentrum Karlsruhe, Institute for Materials Research I, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Maier, Hans [Max-Planck-Institut fuer Plasmaphysik, Materials Research, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany)

    2011-10-01

    Er{sub 2}O{sub 3} thin films on Eurofer steel substrates were produced by a filtered cathodic arc device, varying the substrate temperature (RT - 700 deg. C) and sample bias (0 to -450 V). The crystallographic phase was analyzed by X-ray diffraction and Raman spectroscopy. Deposition at {>=}600 deg. C without bias lead to solely formation of the cubic Er{sub 2}O{sub 3} phase. Thin films of the uncommon, monoclinic B-phase were prepared with a negative bias voltage of {>=}100 V at RT, and at temperatures {<=}500 deg. C for -250 V bias. The B-phase films exhibit a strongly textured film structure. Residual stress measurements show high compressive stress for B-phase films deposited at RT.

  16. Online Estimation of Model Parameters and State of Charge of LiFePO4 Batteries Using a Novel Open-Circuit Voltage at Various Ambient Temperatures

    Directory of Open Access Journals (Sweden)

    Fei Feng

    2015-04-01

    Full Text Available This study describes an online estimation of the model parameters and state of charge (SOC of lithium iron phosphate batteries in electric vehicles. A widely used SOC estimator is based on the dynamic battery model with predeterminate parameters. However, model parameter variances that follow with their varied operation temperatures can result in errors in estimating battery SOC. To address this problem, a battery online parameter estimator is presented based on an equivalent circuit model using an adaptive joint extended Kalman filter algorithm. Simulations based on actual data are established to verify accuracy and stability in the regression of model parameters. Experiments are also performed to prove that the proposed estimator exhibits good reliability and adaptability under different loading profiles with various temperatures. In addition, open-circuit voltage (OCV is used to estimate SOC in the proposed algorithm. However, the OCV based on the proposed online identification includes a part of concentration polarization and hysteresis, which is defined as parametric identification-based OCV (OCVPI. Considering the temperature factor, a novel OCV–SOC relationship map is established by using OCVPI under various temperatures. Finally, a validating experiment is conducted based on the consecutive loading profiles. Results indicate that our method is effective and adaptable when a battery operates at different ambient temperatures.

  17. Influence of applied voltage on the performance of bioelectrochemical anaerobic digestion of sewage sludge and planktonic microbial communities at ambient temperature.

    Science.gov (United States)

    Feng, Qing; Song, Young-Chae; Bae, Byung-Uk

    2016-11-01

    The influence of applied voltage on the bioelectrochemical anaerobic digestion of sewage sludge was studied at ambient temperature (25±2°C). The stability of the bioelectrochemical anaerobic digestion was considerably good in terms of pH, alkalinity and VFAs at 0.3V and 0.5V, but VFA accumulation occurred at 0.7V. The specific methane production rate (370mLCH4/L.d) was the highest at 0.3V, but the methane content (80.6%) in biogas and the methane yield (350mLCH4/gCODr) were higher at 0.5V, significantly better than those of 0.7V. The VS removal efficiency was 64-66% at 0.3V and 0.5V, but only 31% at 0.7V. The dominant species of planktonic microbial communities was Cloacamonas at 0.3V and 0.5V, but the percentage of hydrolytic bacteria species such as Saprospiraceae, Fimbriimonas, and Ottowia pentelensis was much higher at 0.7V. The optimal applied voltage for bioelectrochemical anaerobic digestion was 0.3-0.5V according to digestion performance and planktonic microbial communities.

  18. Electroabsorption modulator laser for cost-effective 40 Gbit/s networks with low drive voltage, chirp and temperature dependence

    DEFF Research Database (Denmark)

    Aubin, G.; Seoane, Jorge; Merghem, K.;

    2009-01-01

    The performances of a novel low-chirp electroabsorption modulator laser module are presented. Transmission is analysed in standard singlermode fibre at 40 Gbit/s. Propagation without chromatic dispersion compensation up to 2 km exhibits a low penalty variation over a wide temperature range...

  19. TIME DOMAIN REFLECTOMETRY FOR THE LOCALIZATION OF ELECTRICAL FAULTS IN THE INSTRUMENTATION OF THE LHC STRING MAGNETS A Study Case of Voltage Tap, Temperature, and Pressure Transducer Circuits

    CERN Document Server

    Komorowski, P

    1999-01-01

    Time Domain Reflectometry (TDR) is one of the most powerful methods used to analyze the integrity of the signal propagating in a transmission line. The method is based on the principle that the wave propagating in the line is reflected at the locations where the impedance of the line changes. The fault points, joints, branches, junctions, abrupt cross-section changes, etc., cause such reflections. The reflectometry technique involves the excitation of the circuit under test with either a fast edge step function or a well-defined impulse confined in time and frequency domains, and thereafter detection of the amplitude and time of the reflections. Both variants of the method were successfully applied to localize open circuit faults in the voltage tap connections, pressure transducers, and temperature sensing carbon gages circuits of the LHC String Dipole Magnet MB2 and Short Straight Section Quadrupole.

  20. Inverted Fuel Cell: Room-Temperature Hydrogen Separation from an Exhaust Gas by Using a Commercial Short-Circuited PEM Fuel Cell without Applying any Electrical Voltage.

    Science.gov (United States)

    Friebe, Sebastian; Geppert, Benjamin; Caro, Jürgen

    2015-06-26

    A short-circuited PEM fuel cell with a Nafion membrane has been evaluated in the room-temperature separation of hydrogen from exhaust gas streams. The separated hydrogen can be recovered or consumed in an in situ olefin hydrogenation when the fuel cell is operated as catalytic membrane reactor. Without applying an outer electrical voltage, there is a continuous hydrogen flux from the higher to the lower hydrogen partial pressure side through the Nafion membrane. On the feed side of the Nafion membrane, hydrogen is catalytically split into protons and electrons by the Pt/C electrocatalyst. The protons diffuse through the Nafion membrane, the electrons follow the short-circuit between the two brass current collectors. On the cathode side, protons and electrons recombine, and hydrogen is released. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Power Packaging of Spray-Cooled SiC Devices for High Temperature and High Voltage Operation: Final Report

    Science.gov (United States)

    2008-07-01

    quickly but effluent fluid removal system becomes the limiting factor . Therefore, heat flux does not increase further. Hence, the optimum distance for...network [3.9]. Though many factors are important in material selection, the primary focus is the glass transition temperature (Tg). There are...the desired switching frequencies. * I Three- r1aL phase dc-ac ac-dc Vph converter # 4 convertr converter 1 # 2 # 3 * I r --- -- -- - 4I6l kV ACSIDE

  2. Electrodynamic stabilization conditions for high-temperature superconducting composites with different types of current-voltage characteristic nonlinearity

    Science.gov (United States)

    Arkharov, A. M.; Lavrov, N. A.; Romanovskii, V. R.

    2014-06-01

    The current instability is studied in high-temperature superconducting current-carrying elements with I- V characteristics described by power or exponential equations. Stability analysis of the macroscopic states is carried out in terms of a stationary zero-dimensional model. In linear temperature approximation criteria are derived that allow one to find the maximum allowable values of the induced current, induced electric field intensity, and overheating of the superconductor. A condition is formulated for the complete thermal stabilization of the superconducting composite with regard to the nonlinearity of its I- V characteristic. It is shown that both subcritical and supercritical stable states may arise. In the latter case, the current and electric field intensity are higher than the preset critical parameters of the superconductor. Conditions for these states depending on the properties of the matrix, superconductor's critical current, fill factor, and nonlinearity of the I- V characteristic are discussed. The obtained results considerably augment the class of allowable states for high-temperature superconductors: it is demonstrated that there exist stable resistive conditions from which superconductors cannot pass to the normal state even if the parameters of these conditions are supercritical.

  3. Annealing, temperature, and bias-induced threshold voltage instabilities in integrated E/D-mode InAlN/GaN MOS HEMTs

    Science.gov (United States)

    Blaho, M.; Gregušová, D.; Haščík, Š.; Ťapajna, M.; Fröhlich, K.; Šatka, A.; Kuzmík, J.

    2017-07-01

    Threshold voltage instabilities are examined in self-aligned E/D-mode n++ GaN/InAlN/GaN MOS HEMTs with a gate length of 2 μm and a source-drain spacing of 10 μm integrated in a logic invertor. The E-mode MOS HEMT technology is based on selective dry etching of the cap layer which is combined with Al2O3 grown by atomic-layer deposition at 380 K. In the D-mode MOS HEMT, the gate recessing is skipped. The nominal threshold voltage (VT) of E/D-mode MOS HEMTs was 0.6 and -3.4 V, respectively; the technology invariant maximal drain current was about 0.45 A/mm. Analysis after 580 K/15 min annealing step and at an elevated temperature up to 430 K reveals opposite device behavior depending on the HEMT operational mode. It was found that the annealing step decreases VT of the D-mode HEMT due to a reduced electron injection into the modified oxide. On the other hand, VT of the E-mode HEMT increases with reduced density of surface donors at the oxide/InAlN interface. Operation at the elevated temperature produces reversible changes: increase/decrease in the VT of the respective D-/E-mode HEMTs. Additional bias-induced experiments exhibit complex trapping phenomena in the devices: Coaction of shallow (˜0.1 eV below EC) traps in the GaN buffer and deep levels at the oxide/InAlN interface was identified for the E-mode device, while trapping in the D-mode HEMTs was found to be consistent with a thermo-ionic injection of electrons into bulk oxide traps (˜0.14 eV above EF) and trapping at the oxide/GaN cap interface states.

  4. Capture of instantaneous temperature in oscillating flows: use of constant-voltage anemometry to correct the thermal lag of cold wires operated by constant-current anemometry.

    Science.gov (United States)

    Berson, Arganthaël; Poignand, Gaëlle; Blanc-Benon, Philippe; Comte-Bellot, Geneviève

    2010-01-01

    A new procedure for the instantaneous correction of the thermal inertia of cold wires operated by a constant-current anemometer is proposed for oscillating flows. The thermal inertia of cold wires depends both on the wire properties and on the instantaneous incident flow velocity. Its correction is challenging in oscillating flows because no relationship between flow velocity and heat transfer around the wire is available near flow reversal. The present correction procedure requires neither calibration data for velocity nor thermophysical or geometrical properties of the wires. The method relies on the splitting of the time lag of cold wires into two factors, which are obtained using a constant-voltage anemometer in the heated mode. The first factor, which is intrinsic to the wire, is deduced from time-constant measurements performed in a low-turbulence flow. The second factor, which depends on the instantaneous flow velocity, is acquired in situ. In oscillating flows, data acquisition can be synchronized with a reference signal so that the same wire is alternatively operated in the cold mode by a constant-current anemometer and in the heated mode by a constant-voltage anemometer. Validation experiments are conducted in an acoustic standing-wave resonator, for which the fluctuating temperature field along the resonator axis is known independently from acoustic pressure measurements, so that comparisons can be made with cold-wire measurements. It is shown that despite the fact that the wire experiences flow reversal, the new procedure recovers accurately the instantaneous temperature of the flow.

  5. The effects of fabrication temperature on current-voltage characteristics and energy efficiencies of quantum dot sensitized ZnOH-GO hybrid solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Islam, S. M. Z. [IUSL, Department of Physics, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Department of Physics and Engineering Physics, Fordham University, 441 E. Fordham Road, Bronx, New York 10458 (United States); Department of Electrical Engineering, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Gayen, Taposh [IUSL, Department of Physics, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Department of Physics and Engineering Physics, Fordham University, 441 E. Fordham Road, Bronx, New York 10458 (United States); Tint, Naing; Alfano, Robert, E-mail: ralfano@sci.ccny.cuny.edu [IUSL, Department of Physics, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Department of Electrical Engineering, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Shi, Lingyan [IUSL, Department of Physics, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Department of Biomedical Engineering, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Seredych, Mykola; Bandosz, Teresa J. [Department of Chemistry, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States)

    2014-11-07

    The effects of fabrication temperature are investigated on the performance of CdSe quantum dot (QD)-sensitized hybrid solar cells of the composite material of zinc (hydr)oxide (ZnOH-GO)with 2 wt. % graphite oxide. The current-voltage (I-V) and photo-current measurements show that higher fabrication temperatures yield greater photovoltaic power conversion efficiencies that essentially indicate more efficient solar cells. Two Photon Fluorescence images show the effects of temperature on the internal morphologies of the solar devices based on such materials. The CdSe-QD sensitized ZnOH-GO hybrid solar cells fabricated at 450 °C showing conversion of ∼10.60% under a tungsten lamp (12.1 mW/cm{sup 2}) are reported here, while using potassium iodide as an electrolyte. The output photocurrent, I (μA) with input power, P (mW/cm{sup 2}) is found to be superlinear, showing a relation of I = P{sup n}, where n = 1.4.

  6. The effects of fabrication temperature on current-voltage characteristics and energy efficiencies of quantum dot sensitized ZnOH-GO hybrid solar cells

    Science.gov (United States)

    Islam, S. M. Z.; Gayen, Taposh; Tint, Naing; Shi, Lingyan; Seredych, Mykola; Bandosz, Teresa J.; Alfano, Robert

    2014-11-01

    The effects of fabrication temperature are investigated on the performance of CdSe quantum dot (QD)-sensitized hybrid solar cells of the composite material of zinc (hydr)oxide (ZnOH-GO)with 2 wt. % graphite oxide. The current-voltage (I-V) and photo-current measurements show that higher fabrication temperatures yield greater photovoltaic power conversion efficiencies that essentially indicate more efficient solar cells. Two Photon Fluorescence images show the effects of temperature on the internal morphologies of the solar devices based on such materials. The CdSe-QD sensitized ZnOH-GO hybrid solar cells fabricated at 450 °C showing conversion of ˜10.60% under a tungsten lamp (12.1 mW/cm2) are reported here, while using potassium iodide as an electrolyte. The output photocurrent, I (μA) with input power, P (mW/cm2) is found to be superlinear, showing a relation of I = Pn, where n = 1.4.

  7. Analysis of equilibrium and kinetic models of internal reforming on solid oxide fuel cell anodes: Effect on voltage, current and temperature distribution

    Science.gov (United States)

    Ahmed, Khaliq; Fӧger, Karl

    2017-03-01

    The SOFC is well-established as a high-efficiency energy conversion technology with demonstrations of micro-CHP systems delivering 60% net electrical efficiency [1]. However, there are key challenges in the path to commercialization. Foremost among them is stack durability. Operating at high temperatures, the SOFC invariably suffers from thermally induced material degradation. This is compounded by thermal stresses within the SOFC stack which are generated from a number of interacting factors. Modelling is used as a tool for predicting undesirable temperature and current density gradients. For an internal reforming SOFC, fidelity of the model is strongly linked to the representation of the fuel reforming reactions, which dictate species concentrations and net heat release. It is critical for simulation of these profiles that the set of reaction rate expressions applicable for the particular anode catalyst are chosen in the model. A relatively wide spectrum of kinetic correlations has been reported in the literature. This work presents a comparative analysis of the internal distribution of temperature, current, voltage and compositions on a SOFC anode, using various combinations of reaction kinetics and equilibrium expressions for the reactions. The results highlight the significance of the fuel reforming chemistry and kinetics in the prediction of cell performance.

  8. Silicon-on-insulator-based high-voltage, high-temperature integrated circuit gate driver for silicon carbide-based power field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Tolbert, Leon M [ORNL; Huque, Mohammad A [ORNL; Blalock, Benjamin J [ORNL; Islam, Syed K [ORNL

    2010-01-01

    Silicon carbide (SiC)-based field effect transistors (FETs) are gaining popularity as switching elements in power electronic circuits designed for high-temperature environments like hybrid electric vehicle, aircraft, well logging, geothermal power generation etc. Like any other power switches, SiC-based power devices also need gate driver circuits to interface them with the logic units. The placement of the gate driver circuit next to the power switch is optimal for minimising system complexity. Successful operation of the gate driver circuit in a harsh environment, especially with minimal or no heat sink and without liquid cooling, can increase the power-to-volume ratio as well as the power-to-weight ratio for power conversion modules such as a DC-DC converter, inverter etc. A silicon-on-insulator (SOI)-based high-voltage, high-temperature integrated circuit (IC) gate driver for SiC power FETs has been designed and fabricated using a commercially available 0.8--m, 2-poly and 3-metal bipolar-complementary metal oxide semiconductor (CMOS)-double diffused metal oxide semiconductor (DMOS) process. The prototype circuit-s maximum gate drive supply can be 40-V with peak 2.3-A sourcing/sinking current driving capability. Owing to the wide driving range, this gate driver IC can be used to drive a wide variety of SiC FET switches (both normally OFF metal oxide semiconductor field effect transistor (MOSFET) and normally ON junction field effect transistor (JFET)). The switching frequency is 20-kHz and the duty cycle can be varied from 0 to 100-. The circuit has been successfully tested with SiC power MOSFETs and JFETs without any heat sink and cooling mechanism. During these tests, SiC switches were kept at room temperature and ambient temperature of the driver circuit was increased to 200-C. The circuit underwent numerous temperature cycles with negligible performance degradation.

  9. Experimental and theoretical studies of a high temperature cesium-barium tacitron, with application to low voltage-high current inversion. Final report, April 1, 1993--February 28, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Murray, C.S.; El-Genk, M.S.

    1994-02-01

    A low voltage/high current switch refer-red as ``Cs-Ba tacitron`` is studied for use as a dc to ac inverter in high temperature and/or ionizing radiation environments. The operational characteristics of the Cs-Ba tacitron as a switch were investigated experimentally in three modes: (a) breakdown mode, (b) I-V mode, and (c) current modulation mode. Operation parameters measured include switching frequencies up to 20 kHz, hold-off voltages up to 200 V, current densities in excess of 15 A/CM{sup 2}, switch power density of 1 kW/cm{sup 2}, and a switching efficiency in excess of 90 % at collector voltages greater than 30 V. Also, if the discharge current is circuit limited to a value below the maximum thermal emission current density, the voltage drop is constant and below 3 V.

  10. Temperature- and voltage-dependent trap generation model in high-k metal gate MOS device with percolation simulation

    Science.gov (United States)

    Xu, Hao; Yang, Hong; Wang, Yan-Rong; Wang, Wen-Wu; Luo, Wei-Chun; Qi, Lu-Wei; Li, Jun-Feng; Zhao, Chao; Chen, Da-Peng; Ye, Tian-Chun

    2016-08-01

    High-k metal gate stacks are being used to suppress the gate leakage due to tunneling for sub-45 nm technology nodes. The reliability of thin dielectric films becomes a limitation to device manufacturing, especially to the breakdown characteristic. In this work, a breakdown simulator based on a percolation model and the kinetic Monte Carlo method is set up, and the intrinsic relation between time to breakdown and trap generation rate R is studied by TDDB simulation. It is found that all degradation factors, such as trap generation rate time exponent m, Weibull slope β and percolation factor s, each could be expressed as a function of trap density time exponent α. Based on the percolation relation and power law lifetime projection, a temperature related trap generation model is proposed. The validity of this model is confirmed by comparing with experiment results. For other device and material conditions, the percolation relation provides a new way to study the relationship between trap generation and lifetime projection. Project supported by the National High Technology Research and Development Program of China (Grant No. SS2015AA010601), the National Natural Science Foundation of China (Grant Nos. 61176091 and 61306129), and the Opening Project of Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of MicroElectronics of Chinese Academy of Sciences.

  11. Room temperature current-voltage (I-V) characteristics of Ag/InGaN/n-Si Schottky barrier diode

    Science.gov (United States)

    Erdoğan, Erman; Kundakçı, Mutlu

    2017-02-01

    Metal-semiconductors (MSs) or Schottky barrier diodes (SBDs) have a significant potential in the integrated device technology. In the present paper, electrical characterization of Ag/InGaN/n-Si Schottky diode have been systematically carried out by simple Thermionic method (TE) and Norde function based on the I-V characteristics. Ag ohmic and schottky contacts are deposited on InGaN/n-Si film by thermal evaporation technique under a vacuum pressure of 1×10-5 mbar. Ideality factor, barrier height and series resistance values of this diode are determined from I-V curve. These parameters are calculated by TE and Norde methods and findings are given in a comparetive manner. The results show the consistency for both method and also good agreement with other results obtained in the literature. The value of ideality factor and barrier height have been determined to be 2.84 and 0.78 eV at room temperature using simple TE method. The value of barrier height obtained with Norde method is calculated as 0.79 eV.

  12. A wide bandgap silicon carbide (SiC) gate driver for high-temperature and high-voltage applications

    Energy Technology Data Exchange (ETDEWEB)

    Lamichhane, Ranjan [University of Arkansas; Ericson, Milton Nance [ORNL; Frank, Steven Shane [ORNL; BRITTONJr., CHARLES L. [Oak Ridge National Laboratory (ORNL); Marlino, Laura D [ORNL; Mantooth, Alan [University of Arkansas; Francis, Matt [APEI, Inc.; Shepherd, Dr. Paul [University of Arkansas; Glover, Dr. Michael [University of Arkansas; Podar, Mircea [ORNL; Perez, M [University of Arkansas; Mcnutt, Tyler [APEI, Inc.; Whitaker, Mr. Bret [APEI, Inc.; Cole, Mr. Zach [APEI, Inc.

    2014-01-01

    Limitations of silicon (Si) based power electronic devices can be overcome with Silicon Carbide (SiC) because of its remarkable material properties. SiC is a wide bandgap semiconductor material with larger bandgap, lower leakage currents, higher breakdown electric field, and higher thermal conductivity, which promotes higher switching frequencies for high power applications, higher temperature operation, and results in higher power density devices relative to Si [1]. The proposed work is focused on design of a SiC gate driver to drive a SiC power MOSFET, on a Cree SiC process, with rise/fall times (less than 100 ns) suitable for 500 kHz to 1 MHz switching frequency applications. A process optimized gate driver topology design which is significantly different from generic Si circuit design is proposed. The ultimate goal of the project is to integrate this gate driver into a Toyota Prius plug-in hybrid electric vehicle (PHEV) charger module. The application of this high frequency charger will result in lighter, smaller, cheaper, and a more efficient power electronics system.

  13. Essays on the Digital Divide

    Science.gov (United States)

    Abdelfattah, Belal M. T.

    2013-01-01

    The digital divide is a phenomenon that is globally persistent, despite rapidly decreasing costs in technology. While much of the variance in the adoption and use of information communication technology (ICT) that defines the digital divide can be explained by socioeconomic and demographic variables, there is still significant unaccounted variance…

  14. Temperature and voltage dependence of barrier height and ideality factor in Au/0.07 graphene-doped PVA/n-Si structures

    Science.gov (United States)

    Altındal Yerişkin, S.; Balbaşı, M.; Demirezen, S.

    2017-01-01

    In this study, Au/0.07 graphene-doped PVA/n-Si structures were fabricated and current conduction mechanism in these structures were investigated in the temperature range of 80-380 K through forward bias current-voltage (I-V) measurements. Main electrical parameters were extracted from I-V data. Zero-bias barrier height (overline{Φ}_{B0} ) and ideality factor (n) were found strong functions of temperature and their values ranged from 0.234 eV and 4.98 (at 80 K) to 0.882 eV and 1.15 (at 380 K), respectively. Φ ap versus q/2kT plot was drawn to obtain an evidence of a Gaussian distribution of the barrier heights (BHs) and it revealed two distinct linear regions with different slopes and intercepts. The mean values of BH (Φ Bo) and zero-bias standard deviation (σ s ) were obtained from the intercept and slope of the linear regions of this plot as 1.30 eV and 0.16 V for the first region (280-380 K) and 0.74 eV and 0.085 V for the second region (80-240 K), respectively. Thus, the values of overline{Φ}_{B0} and effective Richardson constant (A*) were also found from the intercept and slope of the modified Richardson plot [ln(I s /T 2) - q 2 σ {/o 2} /2k 2 T 2 vs q/kT] as 1.31 eV and 130 A/cm2 K2 for the first region and 0.76 eV and 922 A/cm2 K2 for the second region, respectively. The value of A* for the first region was very close to the theoretical value for n-Si (112 A/cm2 K2). The energy density distribution profile of surface states (Nss) was also extracted from the forward bias I-V data by taking into account voltage dependent effective BH (Φe) and n.

  15. Resistor dividers and ac grids; Spannungsteiler und Gleichstromnetzwerke

    Energy Technology Data Exchange (ETDEWEB)

    Biechl, H. [Hochschule Kempten (Germany). Werner-von-Siemens-Labor fuer Elektrische Antriebe und Mechatronik

    2010-01-15

    The contribution discusses the subject of resistor dividers and shows how to calculate the mathematical voltage division rules. It also explains how a d.c. grid can be calculated with the aid of Ohm's law and the two laws of Kirchhoff. (orig.)

  16. 一种高电源抑制比全工艺角低温漂CMOS基准电压源%A bandgap voltage reference with high PSRR and low temperature drift at the all process corners

    Institute of Scientific and Technical Information of China (English)

    方圆; 周凤星; 张涛; 张迪

    2012-01-01

    A bandgap voltage reference circuit which has high PSRR and low temperature drift at all Process Corners was presented based on SMIC's 0.35μm CMOS process. First, a high PSRR voltage reference is amplified by a voltage amplifier to get a stabilized voltage, which then is provided to bandgap core as power supply, so as to get high PSRR. Besides, set the key resistor tunable to adjust the positive voltage temperature coefficient, so as to meeting the negative voltage temperature coefficient change under different processes, and ultimately getting a bandgap voltage reference with low temperature coefficient at all processe. Cadence virtuoso simulation results showed that the circuit had a PSRR -109 dB (10 Hz)and --64 dB (10 kHz) at 27℃ and a temperature coefficient below 3.2×10^-6/℃ at all processes under 4 V supply voltage from-40-80℃.%基于SMIC0.35μm的CMOS工艺.设计了一种高电源抑制比,同时可在全工艺角下的得到低温漂的带隙基准电路。首先采用一个具有高电源抑制比的基准电压。通过电压放大器放大得到稳定的电压,以提供给带隙核心电路作为供电电源.从而提高了电源抑制比。另外,将电路中的关键电阻设置为可调电阻,从而可以改变正温度电压的系数,以适应不同工艺下负温度系数的变化,最终得到在全工艺角下低温漂的基准电压。Cadencevirtuoso仿真表明:在27℃下.10Hz时电源抑制比(ISRR)-109dB,10kHz时(esRR)达到-64dB;在4V电源电压下,在-40~80℃范围内的不同工艺角下.温度系数均可达到5.6×10^-6 V/℃以下。

  17. Variation in the response to manipulation of post-mortem glycolysis in beef muscles by low-voltage electrical stimulation and conditioning temperature.

    Science.gov (United States)

    Hollung, Kristin; Veiseth, Eva; Frøystein, Terje; Aass, Laila; Langsrud, Oyvind; Hildrum, Kjell Ivar

    2007-11-01

    The aim of this study was to investigate how manipulation of glycolytic rate by post-mortem processing conditions influences quality of aged beef of two bovine muscles of different physiological character, longissimus dorsi (LD) and adductor (AD). Post-mortem glycolysis was manipulated by low-voltage electrical stimulation (LV-ES) of half carcasses and by chilling rate of the muscles. Multivariate statistical analysis was used to visualise the data, while ANOVA was used to identify significant effects and interactions. As expected there was a significant effect of LV-ES on the pH decline in the first hours post-mortem in both muscles. Moreover, significant effects of LV-ES on WB shear force measured 2 and 8 days after slaughter were observed for LD at both chilling temperatures, while for AD no effect on WB shear force was observed. Furthermore, the results revealed a large individual variation in the response of LV-ES on both pH decline and WB shear force, and this variation did not always correlate for the two responses. Some animals showed no response of LV-ES on pH decline, but still had an improved WB shear force, and vice versa. The results from this study indicate that there probably are other mechanisms than accelerated pH decline and prevention of cold-shortening, by which LV-ES can affect meat tenderness.

  18. 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...

  19. 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.

  20. Divided by the Market, Divided by the State

    DEFF Research Database (Denmark)

    Wulfgramm, Melike; Starke, Peter

    2016-01-01

    of the individual differences, the analysis also shows, for the first time, that both high inequality and strongly redistributive policies divide public opinion along the lines of socioeconomic position. Put differently, while market inequality may be associated with less cohesive attitudes, a highly redistributive...

  1. 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...

  2. Getting Past the "Digital Divide"

    Science.gov (United States)

    McCollum, Sean

    2011-01-01

    In the last decade, "digital divide" has become a catchphrase for the stubborn disparity in IT resources between communities, especially in regard to education. Low-income, rural and minority populations have received special scrutiny as the technological "have-nots." This article presents success stories of educators who can work around obstacles…

  3. Dividing Fractions: A Pedagogical Technique

    Science.gov (United States)

    Lewis, Robert

    2016-01-01

    When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…

  4. 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.

  5. The physical mechanism on the threshold voltage temperature stability improvement for GaN HEMTs with pre-fluorination argon treatment

    Science.gov (United States)

    Wang, Yun-Hsiang; Liang, Yung C.; Samudra, Ganesh S.; Huang, Chih-Fang; Kuo, Wei-Hung; Lo, Guo-Qiang

    2016-06-01

    In this paper, a normally-off AlGaN/GaN MIS-HEMT with improved threshold voltage (VTH) thermal stability is reported with investigations on its physical mechanism. The normally-off operation of the device is achieved from novel short argon plasma treatment (APT) prior to the fluorine plasma treatment (FPT) on Al2O3 gate dielectrics. For the MIS-HEMT with FPT only, its VTH drops from 4.2 V at room temperature to 0.5 V at 200 °C. Alternatively, for the device with APT-then-FPT process, its VTH can retain at 2.5 V at 200 °C due to the increased amount of deep-level traps that do not emit electrons at 200 °C. This thermally stable VTH makes this device suitable for high power applications. The depth profile of the F atoms in Al2O3, measured by the secondary ion mass spectroscopy, reveals a significant increase in the F concentration when APT is conducted prior to FPT. The X-ray photoelectron spectroscopy (XPS) analysis on the plasma-treated Al2O3 surfaces observes higher composition of Al-F bonds if APT was applied before FPT. The enhanced breaking of Al-O bonds due to Ar bombardment assisted in the increased incorporation of F radicals at the surface during the subsequent FPT process. The Schrödinger equation of Al2OxFy cells, with the same Al-F compositions as obtained from XPS, was solved by Gaussian 09 molecular simulations to extract electron state distribution as a function of energy. The simulation results show creation of the deeper trap states in the Al2O3 bandgap when APT is used before FPT. Finally, the trap distribution extracted from the simulations is verified by the gate-stress experimental characterization to confirm the physical mechanism described.

  6. Design of a Bandgap Voltage Reference with a Low Temperature Coefficient%一种低温度系数的带隙基准电压源设计

    Institute of Scientific and Technical Information of China (English)

    张瑛; 王剑; 周洪敏

    2016-01-01

    基准电压源是集成电路系统中的重要组成部分,其性能直接影响系统的稳定性和鲁棒性。温度系数是基准电压源的重要性能指标之一,而高阶温度补偿技术是降低基准源温度系数的有效方法。基于标准0.18μm CMOS工艺,设计了一种低温度系数的带隙基准电压源,采用电流模结构的带隙基准电路实现了低电源电压工作,并通过VBE线性化补偿技术实现了在低压下的高阶温度补偿。所设计的 CMOS 带隙基准电压源在-40~125℃的范围内,温度系数为6.855 ppm/℃,低频时电源电压抑制比达到了-95 dB,而电源电压在0.6~1.8 V范围内变化时线性调整率仅为0.2%。仿真实验结果表明,该电路结构能够有效提升带隙基准电压源的温度性能。%The reference voltage source is an important part of the integrated circuit system,and it has a direct impact on the stability and robustness of the system. The temperature coefficient is one of the important performances of the reference voltage source,and the high-order temperature compensation technology is an effective way to reduce the temperature coefficient. A bandgap voltage reference with a low temperature coefficient is designed based on standard 0. 18μm Complementary Metal Oxide Semiconductor ( CMOS) process. The current mode structure is used to make the circuit working under the low power supply voltage,and the linear compensation technology is applied to complete the high order temperature compensation. The designed voltage reference gives a good low temperature coefficient of 6. 855 ppm/℃ in the temperature range from-40 to 125 degree,and provides a good Power Supply Rejection Ratio (PSRR) of-95 dB in the low frequency band. The voltage linear regulation of the bandgap voltage reference is only 0. 2% while the supply voltage changes from 0. 6 V to 1. 8 V. The simulation results show that the circuit structure can improve the temperature performance of the bandgap

  7. Comparison of Algorithms for Control of Loads for Voltage Regulation

    DEFF Research Database (Denmark)

    Douglass, Philip James; Han, Xue; You, Shi

    2014-01-01

    Autonomous flexible loads can be utilized to regulate voltag e on low voltage feeders. This paper compares two algorithms for controllin g loads: a simple voltage droop, where load power consumption is a varied in proportio n to RMS voltage; and a normalized relative voltage droop, which modifies...... the simpl e voltage droop by subtracting the mean voltage value at the bus and dividing by the standard deviation. These two controllers are applied to hot water heaters simul ated in a simple residential feeder. The simulation results show that both controllers r educe the frequency of undervoltage events...

  8. 基于ZigBee的高压带电体温度在线监测系统%ZigBee-based temperature monitoring on-line system of high-voltage live parts

    Institute of Scientific and Technical Information of China (English)

    滕志军; 屈银龙; 王中宝; 杨旭

    2011-01-01

    在现代电力系统中,高压带电体温度监测已经成为电气设备安全运行所面临的实际问题.本文提出了以zigBee无线传感器网络为核心,以以太网为骨干网,采用CC2430芯片为传感器控制核心的高压带电体温度测量方案.试验证明,系统能够实时监测高压带电体温度变化,工作稳定可靠、具有较高的实用性和市场价值.%In modern power system, the temperature monitoring of high-voltage live parts has become one of practical problems in the safe operation of electrical equipment. This paper proposes a high-voltage live parts temperature measurement that includes ZigBee wireless sensor networks as the core, Ethernet as the backbone and CC2430 chip as the sensor control core. ZigBee network of the system runs on 2.4GHz free frequency band. When tree topology is used to build system network, the maximum root depth is 5. The network can monitor the high-voltage live parts within 150m radius circular area in real time. The system network is scalable and can support up to 65,535 nodes. The system temperature monitoring range is -55℃ ~ + 125℃ with 14 bits resolution. When the range of monitoring temperature is - 10℃ ~ + 85℃, accuracy can be achieved within ± 0. 5℃. Through the experiment, the realtime temperature monitoring system of high-voltage live parts not only is stable and reliable but also has high availability and market value.

  9. Information Societies and Digital Divides

    CERN Document Server

    Sorj, Bernardo

    2008-01-01

    The book argues ICT are part of the set of goods and services that determine quality of life, social inequality and the chances for economic development. Therefore understanding the digital divide demands a broader discussion of the place of ICT within each society and in the international system. The author argues against the perspectives that either isolates ICT from other basic social goods (in particular education and employment) as well as those that argue that new technologies are luxury of a consumer society. Though the author accepts that new technologies are not a panacea for the problems of inequality, access to them become a condition of full integration of social life. Using examples mainly from Latin America, the work presents some general policy proposals on the fight against the digital divide which take in consideration other dimensions of social inequality and access to public goods. Bernardo Sorj was born in Montevideo, Uruguay. He is a naturalized Brazilian, living in Brazil since 1976. He ...

  10. Pulse swallowing frequency divider with low power and compact structure

    Institute of Scientific and Technical Information of China (English)

    Gao Haijun; Sun Lingling; Cai Chaobo; Zhan Haiting

    2012-01-01

    A pulse swallowing frequency divider with low power and compact structure is presented.One of the DFFs in the divided by 2/3 prescaler is controlled by the modulus control signal,and automatically powered off when it has no contribution to the operation of the prescaler.The DFFs in the program counter and the swallow counter are shared to compose a compact structure,which reduces the power consumption further.The proposed multi-modulus frequency divider was implemented in a standard 65 nm CMOS process with an area of 28 ×22 μm2.The power consumption of the divider is 0.6 mW under 1.2 V supply voltage when operating at 988 MHz.

  11. A novel imidazole-based electrolyte additive for improved electrochemical performance at elevated temperature of high-voltage LiNi0.5Mn1.5O4 cathodes

    Science.gov (United States)

    Rong, Haibo; Xu, Mengqing; Xie, Boyuan; Lin, Haibin; Zhu, Yunmin; Zheng, Xiongwen; Huang, Weizhao; Liao, Youhao; Xing, Lidan; Li, Weishan

    2016-10-01

    A novel electrolyte additive, 1,1‧-sulfonyldiimidazole (SDM), is firstly reported to improve the cycling performance of LiNi0.5Mn1.5O4 at high voltage and elevated temperature (55 °C). Linear sweep voltammetry (LSV), initial differential capacity vs. voltage, and computation results indicate that SDM is oxidized at a lower potential than the solvents of the electrolyte. Coulombic efficiency and capacity retention of a Li/LiNi0.5Mn1.5O4 cell can be significantly enhanced in the presence of SDM, and moreover cells with SDM deliver lower impedance after 100 cycles at elevated temperature. To better understand the functional mechanism of the enhanced performance with incorporation of SDM in the electrolyte, ex-situ analytical techniques, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and inductively coupled plasma mass spectrometry (ICP-MS) are employed to gain insight into the reaction mechanism of SDM on the LiNi0.5Mn1.5O4 electrode at high voltage and elevated temperature (55 °C). Surface analysis reveals that the improved electrochemical performance of the cells can be ascribed to the highly stable surface layer generated by SDM, which thus mitigates the detrimental decomposition of the electrolyte occurring and stabilizes the interphase of spinel LiNi0.5Mn1.5O4 cathode while cycling at high voltage and elevated temperature.

  12. Transformer-based design techniques for oscillators and frequency dividers

    CERN Document Server

    Luong, Howard Cam

    2016-01-01

    This book provides in-depth coverage of transformer-based design techniques that enable CMOS oscillators and frequency dividers to achieve state-of-the-art performance.  Design, optimization, and measured performance of oscillators and frequency dividers for different applications are discussed in detail, focusing on not only ultra-low supply voltage but also ultra-wide frequency tuning range and locking range.  This book will be an invaluable reference for anyone working or interested in CMOS radio-frequency or mm-Wave integrated circuits and systems.

  13. 高电源抑制比、低温飘带隙基准电压源的设计%Design of high PSRR low temperature coefficient band gap voltage reference

    Institute of Scientific and Technical Information of China (English)

    高献坤; 雷君召; 丁赪璐; 周西军; 李遂亮; 余泳昌

    2011-01-01

    Based on the TSMC 0.18μm CMOS process design kit,a band gap voltage reference circuitwith high power supply rejection ratio and low temperature coefficient is presented in this paper,where power supply voltage and output reference voltage is 3 V and 1.25 V respectively. The simulation results for this circuit using Cadence' s Spectre indicate that temperature coefficient from-40 to 125℃ is 3.5 x10-6·℃-1',and the voltage regulation is 72μV·V-1 during the supply voltage linear changed from 2.7 to 3.6 V. The circuit has good PSSR,top point reaching 89 dB,and being 45 dB at 10 kHz.%采用TSMC 0.18 μm CMOS工艺,设计了一种电源电压为3V、基准输出为1.25 V的高电源抑制比、低温度系数的带隙基准电压源电路.Cadence Spectre仿真结果表明,该基准源具有较好的温度特性,在-40~125℃温度范围内,温度系数为3.5×10-6·℃-1;电源电压在2.7~3.6V范围内波动时,电源电压调整率为72 μV·V-1;具有良好的电源电压抑制特性,最高抑制比可达89 dB,在10 kHz处可实现45 dB的电源电压抑制比.

  14. Quick-low-density parity check and dynamic threshold voltage optimization in 1X nm triple-level cell NAND flash memory with comprehensive analysis of endurance, retention-time, and temperature variation

    Science.gov (United States)

    Doi, Masafumi; Tokutomi, Tsukasa; Hachiya, Shogo; Kobayashi, Atsuro; Tanakamaru, Shuhei; Ning, Sheyang; Ogura Iwasaki, Tomoko; Takeuchi, Ken

    2016-08-01

    NAND flash memory’s reliability degrades with increasing endurance, retention-time and/or temperature. After a comprehensive evaluation of 1X nm triple-level cell (TLC) NAND flash, two highly reliable techniques are proposed. The first proposal, quick low-density parity check (Quick-LDPC), requires only one cell read in order to accurately estimate a bit-error rate (BER) that includes the effects of temperature, write and erase (W/E) cycles and retention-time. As a result, 83% read latency reduction is achieved compared to conventional AEP-LDPC. Also, W/E cycling is extended by 100% compared with conventional Bose-Chaudhuri-Hocquenghem (BCH) error-correcting code (ECC). The second proposal, dynamic threshold voltage optimization (DVO) has two parts, adaptive V Ref shift (AVS) and V TH space control (VSC). AVS reduces read error and latency by adaptively optimizing the reference voltage (V Ref) based on temperature, W/E cycles and retention-time. AVS stores the optimal V Ref’s in a table in order to enable one cell read. VSC further improves AVS by optimizing the voltage margins between V TH states. DVO reduces BER by 80%.

  15. 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.

  16. 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.

  17. High Voltage Switchgear Temperature Acquisition System Based on SAW Sensor Technology Analysis%基于 SAW 传感器技术的高压开关柜温度采集系统设计分析

    Institute of Scientific and Technical Information of China (English)

    郭翠玲; 高丽

    2015-01-01

    根据传统高压开关柜温度采集方法的不足,采用 SAW 传感器技术对高压开关柜进行无源无线温度采集。该系统具有温度测量、报警功能、参数设定、数据存储等功能,对温度进行远程实时在线监测,是智能电网建设的重要依据。%Based on the shortcomings of the traditional method of temperature measurement of high voltage switchgear ,the paper uses SAW sensor technology to take passive wireless temperature measurement for high voltage switchgear .T he system ,w hich has temperature measurement ,alarm function ,parameter setting ,data storage and other functions that can take real - time remote temperature online monito‐ring ,is an important basis for smart grid construction .

  18. 基于ZigBee的高压带电体温度监测系统研究%Research on the Temperature Monitoring System of High Voltage Charging System Based on ZigBee

    Institute of Scientific and Technical Information of China (English)

    王云飞

    2015-01-01

    For high-voltage charged body operation often appear high temperature problem, the paper proposed based on ZigBee high-voltage charged body temperature online monitoring system, mainly introduces the basic principle of online monitoring system of temperature. Many test results show that the temperature on-line monitoring system has a small packet loss rate and packet error rate, good stability and security, and the test results are accurate, which has a certain popularization value.%针对高压带电体运转时经常出现温度过高等问题,文章提出了基于ZigBee的高压带电体温度在线监测系统,主要介绍了温度在线监测系统的基本原理。多次测试结果表明,温度在线监测系统丢包率和误包率小,稳定性和安全性好,测试结果准确度高,具有一定的推广价值。

  19. Crossroads - Bridging the Digital Divide

    Directory of Open Access Journals (Sweden)

    David Cobb

    2005-03-01

    Full Text Available It’s so good to be in Cambridge, it feels almost like home. Let me start by stating that in the past year ITMB, a successful map publisher in British Columbia, Canada published more paper map titles than at any time in their history. Similarly, the U.S. Geological Survey (USGS recently announced that they have ceased producing paper from their aerial photography archive and will only produce digital copies. I believe that both of these facts speak to the future of maps and digital data. It means there will be paper maps well into the future and there will be an increasing array of digital data - some of it reformatted, as in the USGS case, and most of it will be born digital. When asked to speak about GIS and its role in libraries I often find myself in a conundrum - am I here to slay the dragon, or to pet the dragon. The role of technology in libraries is not one that has been embraced by everyone, and often the technology itself seems to have been force-fed upon us. The library profession is not one that has historically been a proponent of change and the very nature of GIS is change. In one sense, we have been given the choice of becoming paper museums or, at the very least, making GIS technology available in our collections. Today, I would like to review the many ways that GIS is, or will, affect our collections. I will divide the presentation into a general overview of GIS in libraries, how it affects our acquisitions or collection development policies, its effect on cataloging, on reference services, staffing, and our web services. Then I will shift the focus a little and discuss the current situation at the Harvard Map Collection, the future role of legacy collections, and a look to the future.

  20. 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.

  1. 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%

  2. A reference voltage source with complementary temperature compensation by reference current core%一种用电流基准核作温度互补性补偿的基准电压源

    Institute of Scientific and Technical Information of China (English)

    欧龙振; 李琦; 刘云

    2012-01-01

    In order to overcome defects of the conventional bandgap reference in temperature performance, a bandgap reference circuit with low temperature coefficient was designed. High-level compensation is achieved in this circuit by introducing a current generated by reference current nuclear working in subthreshold region based on the traditional structure of current-mode bandgap reference. Temperature coefficient was greatly reduced by further compensation of compensatory current based on the first-order compensation. Designed with 0. 18 μm standard CMOS process, and simulated with Spectre simulation tools of Cadence, the circuit exhibits a reference voltage 1. 265 V with a voltage change only 0. 2 mV in the temperature range from —40 to 125 ℃ at 2. 7 V supply voltage, compared to the change(about 2. 5 mV) of first-order compensation, accuracy of which is improved by 10 times. When supply voltage ranges from 1. 8 to 3. 5 V, the reference voltage changes 4. 5 mV. With the excellent temperature performance and good anti-disturbance, the requirements of high-performance reference are met.%为克服传统带隙基准源在温度性能上的缺陷,设计了一种低温度系数的带隙基准电路.该电路在传统电流模基准结构的基础上,引入一个工作在亚阈值区电流基准核产生的电流来达到高阶补偿的目的.在一阶补偿的基础上,补偿电流的进一步补偿,大大降低了基准输出的温度系数.电路设计采用0.18 μm的CMOS工艺,利用Cadence软件的Spectre仿真工具对电路进行仿真,仿真结果表明,在2.7V电源电压下,基准输出电压为1.265 V,温度在-40~125℃变化时,基准输出电压仅变化0.2 mV,相比一阶补偿的变化(约为2.5 mV),精度提升了10多倍;电源电压在1.8~3.5 V变化时,基准输出电压变化4.5 mV;在出色的温度性能下有良好的抗干忧性,满足了高性能基准源的要求.

  3. Some results on numerical divided difference formulas

    Institute of Scientific and Technical Information of China (English)

    Wang; Xinghua; Wang; Heyu; Ming-Jun; Lai

    2005-01-01

    The remainder estimates of numerical divided difference formula are given for the functions of lower and higher smoothness, respectively. Then several divided difference formulas with super-convergence are derived with their remainder expressions.

  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. 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.

  6. Tech, Teachers & Teens: Bridging the Divide

    Science.gov (United States)

    Stuht, Amy Colcord; Colcord, Cean

    2011-01-01

    In past decades, the "digital divide" referred to the gap between those who could afford access to technology and those who could not. The divide has shifted in recent years to reflect the growing technological chasm between teachers and their students: today's schools and teenagers' worlds. The digital divide is widening and deepening…

  7. The Myth about the Digital Divide

    Science.gov (United States)

    Hawkins, Brian L.; Oblinge, Diana G.

    2006-01-01

    Although computer ownership is not 100 percent, progress has been made on closing the digital divide. However, defining the digital divide according to the haves and have-nots of computer ownership is only a starting point. Beyond computer ownership, colleges and universities should explore the "second-level digital divide," which can be…

  8. Diversity, Disability, and Geographic Digital Divide

    Science.gov (United States)

    Sumari, Melati; Carr, Erika; Ndebe-Ngovo, Manjerngie

    2006-01-01

    The phenomenon called digital divide was the focus of this paper. Diversity, disability, and geographical digital divide were relevant to this collaborative project. An extensive review of the literature was conducted for the completion of this project. The evidence for the digital divide in terms of race, level of education, and gender in the…

  9. 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.

  10. 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.

  11. 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.

  12. An Optoelectronic High-voltage Probe for Measuring Impulse Voltage Distribution of HVDC Converter Valve

    Institute of Scientific and Technical Information of China (English)

    方志; 邱毓昌

    2007-01-01

    A high-voltage optoelectronic probe is developed for measuring impulse voltage distribution along thyristor units in the HVDC converter valve. The dimension of the resistive voltage divider is optimized by means of numerical compttation of electric field. A pulse frequency modulation (PFM) mode is adopted for the data transmission link because of its immunity to high-intensity electromagnetic interference. Experimental results indicate that the linearity deviation for the whole measuring system is within ± 0.15 %, and therefore it can meet requirements specified by IEC60700-1.

  13. 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.

  14. Entropy variation rate divided by temperature always decreases

    CERN Document Server

    Shih, T M; Merlitz, H; Rondoni, L; Pagni, P J; Chen, Z

    2014-01-01

    For an isolated assembly that comprises a system and its surrounding reservoirs, the total entropy always monotonically increases as time elapses. This phenomenon is known as the second law of thermodynamics. Here we analytically prove that, unlike the entropy itself, the entropy variation rate defies the monotonicity for multiple reservoirs. In other words, there always exist minima. In addition, the crux of our work is the proof that a newly defined variable always decreases. Our proof involves the Newton's law of cooling, in which the heat transfer coefficient is assumed to be constant. These theoretical macro scale findings are validated by numerical experiments using the Crank-Nicholson method, and are illustrated with practical examples. They constitute an alternative to the traditional second-law statement, and may provide useful references for the future micro-scale entropy-related research.

  15. Photomultiplier Tubes at Cryogenic Temperatures

    Science.gov (United States)

    Saunders, Nathan

    2016-09-01

    Liquid noble gas scintillators are widely used in experiments searching for physics beyond the Standard Model. Photomultiplier Tubes (PMTs) working at cryogenic temperatures have been developed as the primary light readout device in those experiments. Three PMTs from Hamamatsu Photonics K.K. (R6041, R11065, and R8520) have been systematically characterized at liquid nitrogen temperature. The high voltage dividing circuits for two of the PMTs were custom-built to make sure there is similar performance at both room and liquid nitrogen temperatures. Their dark count rates at both temperatures were measured. Also measured were their single photoelectron responses at both temperatures using 300, 340, 370, and 420 nm LEDs. The intention is to couple these PMTs directly with inorganic scintillators at liquid nitrogen temperature to achieve high light yeilds for rare-event searches.

  16. Fast frequency divider circuit using combinational logic

    Science.gov (United States)

    Helinski, Ryan

    2017-05-30

    The various technologies presented herein relate to performing on-chip frequency division of an operating frequency of a ring oscillator (RO). Per the various embodiments herein, a conflict between RO size versus operational frequency can be addressed by dividing the output frequency of the RO to a frequency that can be measured on-chip. A frequency divider circuit (comprising NOR gates and latches, for example) can be utilized in conjunction with the RO on the chip. In an embodiment, the frequency divider circuit can include a pair of latches coupled to the RO to facilitate dividing the oscillating frequency of the RO by 2. In another embodiment, the frequency divider circuit can include four latches (operating in pairs) coupled to the RO to facilitate dividing the oscillating frequency of the RO by 4. A plurality of ROs can be MUXed to the plurality of ROs by a single oscillation-counting circuit.

  17. 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.

  18. Applications of high-temperature superconductors in power technology[8470 High-current and high-voltage technology: power systems; power transmission lines and cables;

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R [Energy Technology Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2003-11-01

    Since the discovery of the first high-temperature superconductors (HTSs) in the late 1980s, many materials and families of materials have been discovered that exhibit superconductivity at temperatures well above 20 K. Of these, several families of HTSs have been developed for use in electrical power applications. Demonstration of devices such as motors, generators, transmission lines, transformers, fault-current limiters, and flywheels in which HTSs and bulk HTSs have been used has proceeded to ever larger scales. First-generation wire, made from bismuth-based copper oxides, was used in many demonstrations. The rapid development of second-generation wire, made by depositing thin films of yttrium-based copper oxide on metallic substrates, is expected to further accelerate commercial applications. Bulk HTSs, in which large single-grain crystals are used as basic magnetic components, have also been developed and have potential for electrical power applications.

  19. Determination of threshold and maximum operating electric stresses for selected high voltage insulation. Task 3: Investigation of high voltage capacitor insulation

    Science.gov (United States)

    Sosnowski, M.; Eager, G. S., Jr.

    1984-03-01

    The threshold voltage of capacitor insulation was investigated. The experimental work was performed on samples prepared from commercial polypropylene insulated, liquid-filled capacitors. The samples were vacuum-impregnated with the original capacitor insulating liquid obtained from the manufacturer. A limited number of full-size capacitor elements also were tested. Impulse voltage breakdown tests with dc voltage prestressing were performed at room temperature and 75 C. From the results of these tests, the threshold voltage of the samples of the capacitor insulation was determined at both temperatures and that of the whole capacitor elements at room temperature. The threshold voltage of the capacitor insulation was found to be approximately equal to the impulse breakdown voltage. No difference was found between the threshold voltage at room temperature and at 75 C. The threshold voltage of the whole capacitor elements at room temperature was found to be equal to approximately 80% of the threshold voltage of the capacitor insulation samples.

  20. 一种高精度模数混合温度补偿晶体振荡器%A High-Precision Mixed-Signal Voltage-Controlled Crystal Oscillator with Temperature Compensation

    Institute of Scientific and Technical Information of China (English)

    刘会娟; 伍冬; 郑德平; 潘立阳; 许军

    2011-01-01

    A mixed-signal voltage-controlled crystal oscillator with temperature compensation was implemented in 0.18 ;*m standard CMOS process. The on-chip compensated network reduced memory capacity in digital network. The circuit needs neither floating-gate nor high-voltage CMOS transistor as required by conventional EEPROM/flash memory, which reduced chip cost and power consumption. Simulation results showed that the proposed circuit had a temperature frequency stability of 10'7 from -40 V to 85 *C, and the system consumed 1. 79 mA of power from 1. 8 V supply.%提出了一种对石英晶体振荡器进行温度补偿的模数混合方法.该补偿芯片基于0.18μm标准CMOS工艺实现.采用模拟补偿网络和基于非挥发存储器的数字补偿网络相叠加的方法,对晶体振荡器进行间接补偿,实现了数模混合的片式化,降低了存储器的容量.该方法不需要高压CMOS和EEPROM浮栅器件,降低了工艺成本和功耗.补偿结果显示,温度频率稳定度达到10-7/-40℃~85℃,系统功耗为1.79 mA@1.8 V.

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

    Science.gov (United States)

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

    2016-02-10

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

  2. 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.

  3. Charge transport dependent high open circuit voltage tandem organic photovoltaic cells with low temperature deposited HATCN-based charge recombination layers.

    Science.gov (United States)

    Wei, Huai-Xin; Zu, Feng-Shuo; Li, Yan-Qing; Chen, Wen-Cheng; Yuan, Yi; Tang, Jian-Xin; Fung, Man-Keung; Lee, Chun-Sing; Noh, Yong-Young

    2016-02-01

    Mechanisms of charge transport between the interconnector and its neighboring layers in tandem organic photovoltaic cells have been systematically investigated by studying electronic properties of the involving interfaces with photoelectron spectroscopies and performance of the corresponding devices. The results show that charge recombination occurs at HATCN and its neighboring hole transport layers which can be deposited at low temperature. The hole transport layer plays an equal role to the interconnector itself. These insights provide guidance for the identification of new materials and the device architecture for high performance devices.

  4. 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.

  5. 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

  6. 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

  7. 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...

  8. Bridge the Digital Divide for Educational Equity

    Science.gov (United States)

    Mason, Christine Y.; Dodds, Richard

    2005-01-01

    Students' technological savvy has challenged schools to make greater use of computers and the Internet in their curricula, but unfortunately, not every student has the same access to it, and the inability to keep pace has created a digital divide that continues to widen. The digital divide particularly affects students who are black, Hispanic,…

  9. Social Welfare Implications of the Digital Divide

    Science.gov (United States)

    Kim, Eunjin; Lee, Byungtae; Menon, Nirup M.

    2009-01-01

    The Internet plays a critical role in informing individuals about society, politics, business, and the environment. So much so that it has been said that the digital divide makes the segment of society on the ''right side'' of the divide (the digitally endowed group) better off and that on the ''wrong side'' (the digitally challenged group) worse…

  10. New Media and the Digital Divide

    NARCIS (Netherlands)

    Deursen, van A.J.A.M.; Dijk, van J.A.G.M.; Wright, James D.

    2015-01-01

    During the 1990s, researchers and policy makers began discussing the presence of a so-called ‘digital divide,’ a distinction of people who do and do not have access to information and communication technologies. The concept of the digital divide stems from a comparative perspective of social and inf

  11. 母线运行温度数据采集系统研究%Research of Temperature Monitoring System for Low-voltage Busbar

    Institute of Scientific and Technical Information of China (English)

    李飞

    2016-01-01

    By integrating the general temperature sensors on the market,and writing the upper machine data collection and data processing program on sensors,we can upload the running data of bus bar into the SQL Server database.This sys-tem is also able to run management program for the display and analysis data,for the real-time monitoring of the tempera-ture of bus bar operation.The program could do the abnormal information filtering processing and alarm,then effectively improve the reliability and stability of the bus bar running.%在低压母线槽上安装并整合市场上通用的温度传感器、采集器,然后编写上位机采集和数据处理程序,将采集的温度数据上传至SQL Server数据库,并能够通过运行管理程序对这些数据进行显示和分析,对母线运行过程中的温度进行实时监测,并对异常信息进行筛选处理、报警,有效地提高了母线运行的可靠性和稳定性。

  12. Measurement of a power system nominal voltage, frequency and voltage flicker parameters

    Energy Technology Data Exchange (ETDEWEB)

    Alkandari, A.M. [College of Technological Studies, Electrical Engineering Technology Department, Shwiekh (Kuwait); Soliman, S.A. [Electrical Power and Machines Department, Misr University for Science and Technology, Cairo (Egypt)

    2009-09-15

    We present, in this paper, an approach for identifying the frequency and amplitude of voltage flicker signal that imposed on the nominal voltage signal, as well as the amplitude and frequency of the nominal signal itself. The proposed algorithm performs the estimation in two steps; in the first step the original voltage signal is shifted forward and backward by an integer number of sample, one sample in this paper. The new generated signals from such a shift together with the original one is used to estimate the amplitude of the original signal voltage that composed of the nominal voltage and flicker voltage. The average of this amplitude gives the amplitude of the nominal voltage; this amplitude is subtracted from the original identified signal amplitude to obtain the samples of the flicker voltage. In the second step, the argument of the signal is calculated by simply dividing the magnitude of signal sample with the estimated amplitude in the first step. Calculating the arccosine of the argument, the frequency of the nominal signal as well as the phase angle can be computing using the least error square estimation algorithm. Simulation examples are given within the text to show the features of the proposed approach. (author)

  13. A New Binary Inductive Divider Comparator System for Measuring High-Voltage Thermal Converters

    Science.gov (United States)

    2002-10-01

    use limited to: US Naval Academy. Downloaded on January 30, 2009 at 15:03 from IEEE Xplore . Restrictions apply. Report Documentation Page Form...source, as Authorized licensed use limited to: US Naval Academy. Downloaded on January 30, 2009 at 15:03 from IEEE Xplore . Restrictions apply. KINARD...licensed use limited to: US Naval Academy. Downloaded on January 30, 2009 at 15:03 from IEEE Xplore . Restrictions apply. 1048 IEEE TRANSACTIONS ON

  14. A thermoelectric voltage effect in polyethylene oxide

    CERN Document Server

    Martin, B; Kliem, H

    2003-01-01

    The conductivity of polyethylene oxide (PEO) is described with a three-dimensional hopping model considering electrostatic interactions between the ions. Ions fluctuate over energy-barriers in a multi-well potential. To decide whether positive or negative charges are responsible for this conductivity, the thermoelectric voltage is measured. The samples are embedded between two aluminium-electrodes. The oxide on the interface between the electrodes and the PEO serves as a blocking layer. The temperature of each electrode is controlled by a Peltier element. A temperature step is applied to one electrode by changing the temperature of one of the Peltier elements. Due to this temperature gradient, the mobile charges fluctuate thermally activated from the warmer side to the colder side of the sample. The direction of the measured thermoelectric voltage indicates the type of mobile charges. It is found that positive charges are mobile. Further, it is shown that the absolute value of the thermoelectric voltage depen...

  15. High-voltage electrode optimization towards uniform surface treatment by a pulsed volume discharge

    Science.gov (United States)

    Ponomarev, A. V.; Pedos, M. S.; Scherbinin, S. V.; Mamontov, Y. I.; Ponomarev, S. V.

    2015-11-01

    In this study, the shape and material of the high-voltage electrode of an atmospheric pressure plasma generation system were optimised. The research was performed with the goal of achieving maximum uniformity of plasma treatment of the surface of the low-voltage electrode with a diameter of 100 mm. In order to generate low-temperature plasma with the volume of roughly 1 cubic decimetre, a pulsed volume discharge was used initiated with a corona discharge. The uniformity of the plasma in the region of the low-voltage electrode was assessed using a system for measuring the distribution of discharge current density. The system's low-voltage electrode - collector - was a disc of 100 mm in diameter, the conducting surface of which was divided into 64 radially located segments of equal surface area. The current at each segment was registered by a high-speed measuring system controlled by an ARM™-based 32-bit microcontroller. To facilitate the interpretation of results obtained, a computer program was developed to visualise the results. The program provides a 3D image of the current density distribution on the surface of the low-voltage electrode. Based on the results obtained an optimum shape for a high-voltage electrode was determined. Uniformity of the distribution of discharge current density in relation to distance between electrodes was studied. It was proven that the level of non-uniformity of current density distribution depends on the size of the gap between electrodes. Experiments indicated that it is advantageous to use graphite felt VGN-6 (Russian abbreviation) as the material of the high-voltage electrode's emitting surface.

  16. 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.

  17. 高电源抑制比低温漂带隙基准源设计%Design of Low Temperature-Drift Bandgap Voltage Reference with High PSRR

    Institute of Scientific and Technical Information of China (English)

    胡佳俊; 陈后鹏; 蔡道林; 宋志棠; 周桂华

    2012-01-01

    根据带隙基准的基本原理,结合含三条支路负反馈的电流源,设计了一种高阶补偿的带隙基准源电路.实现了对温度的2阶补偿和3阶补偿,获得了一种高电源抑制比、低温漂、不受电源变化影响的电压基准源.设计采用0.35μm CMOS工艺,仿真结果表明,在-40℃~125℃温度范围内,输出电压的温度系数为7.70×10-7/℃,在1 kHz时,电源抑制比为-82.3 dB.%Based on the principle of bandgap reference and current reference source with 3-branch negative feedback, a bandgap voltage reference source with 2nd-order and 3rd -order temperature compensation was designed. The circuit had a high PSKR and low temperature-drift The design was based on 0. 35 μm CMOS process. Simulation results showed that the bandgap reference source had a temperature coefficient below 7. 70 X 10-7/℃ when the temperature varied from -40 ℃ to 125 ℃, and a PSRR of -82. 3 dB at 1 kHz.

  18. Centrosome positioning in non-dividing cells.

    Science.gov (United States)

    Barker, Amy R; McIntosh, Kate V; Dawe, Helen R

    2016-07-01

    Centrioles and centrosomes are found in almost all eukaryotic cells, where they are important for organising the microtubule cytoskeleton in both dividing and non-dividing cells. The spatial location of centrioles and centrosomes is tightly controlled and, in non-dividing cells, plays an important part in cell migration, ciliogenesis and immune cell functions. Here, we examine some of the ways that centrosomes are connected to other organelles and how this impacts on cilium formation, cell migration and immune cell function in metazoan cells.

  19. Irreversibility in room temperature current-voltage characteristics of NiFe2O4 nanoparticles: A signature of electrical memory effect

    Science.gov (United States)

    Dey, P.; Debnath, Rajesh; Singh, Swati; Mandal, S. K.; Roy, J. N.

    2017-01-01

    Room temperature I-V characteristics study, both in presence and absence of magnetic field (1800 Oe), has been performed on NiFe2O4 nanoparticles, having different particle size (V~14, 21 and 31 nm). Our experiments on these nanoparticles provide evidences for: (1) electrical irreversibility or hysteretic behaviour; (2) positive magnetoresistance and (3) magnetic field dependent electrical irreversibility or hysteresis in the sample. "Hysteretic" nature of I-V curve reveals the existence of electrical memory effect in the sample. Significantly, such hysteresis has been found to be tuned by magnetic field. In order to explain the observed electrical irreversibility, we have proposed a phenomenological model on the light of induced polarization in the sample. Both the positive magnetoresistance and the observed magnetic field dependence of electrical irreversibility have been explained through magnetostriction phenomenon. Interestingly, such effects are found to get reduced with increasing particle size. For NiFe2O4 nanoparticles having V=31 nm, we did not observe any irreversibility effect. This feature has been attributed to the enhanced grain surface effect that in turn gives rise to the residual polarization and hence electrical memory effect in NiFe2O4 nanoparticles, having small nanoscopic particle size.

  20. 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.

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

    Science.gov (United States)

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

    2013-07-23

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

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

    KAUST Repository

    Smith, Casey

    2013-07-23

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

  3. First high-voltage measurements using Ca{sup +} ions at the ALIVE experiment

    Energy Technology Data Exchange (ETDEWEB)

    König, K., E-mail: kkoenig@ikp.tu-darmstadt.de [Technische Universität Darmstadt, Institut für Kernphysik (Germany); Geppert, Ch. [Universität Mainz, Institut für Kernchemie (Germany); Krämer, J.; Maaß, B. [Technische Universität Darmstadt, Institut für Kernphysik (Germany); Otten, E. W. [Universität Mainz, Institut für Physik (Germany); Ratajczyk, T.; Nörtershäuser, W. [Technische Universität Darmstadt, Institut für Kernphysik (Germany)

    2017-11-15

    Many physics experiments depend on accurate high-voltage measurements to determine for example the exact retardation potential of an electron spectrometer as in the KATRIN experiment or the acceleration voltage of the ions at ISOL facilities. Until now only precision high-voltage dividers can be used to measure voltages up to 65 kV with an accuracy of 1 ppm. However, these dividers need frequent calibration and cross-checking and the direct traceability is not given. In this article we will describe the status of an experiment which aims to measure high voltages using collinear laser spectroscopy and which has the potential to provide a high-voltage standard and hence, a calibration source for precision high-voltage dividers on the 1 ppm level.

  4. Americans Divided Over Organic, GM Foods: Poll

    Science.gov (United States)

    ... gov/news/fullstory_162314.html Americans Divided Over Organic, GM Foods: Poll Their opinions aren't driven by politics ... News) -- Americans are split on the value of organic foods and concerns about genetically modified (GM) foods, a ...

  5. Environmental Aesthetics. Crossing Divides and Breaking Ground

    NARCIS (Netherlands)

    Drenthen, M.; Keulartz, J.

    2014-01-01

    Environmental aesthetics crosses several commonly recognized divides: between analytic and continental philosophy, Eastern and Western traditions, universalizing and historicizing approaches, and theoretical and practical concerns. This volume sets out to show how these,perspectives can be brought i

  6. Energy conserving effects of dividing wall column☆

    Institute of Scientific and Technical Information of China (English)

    Jing Fang; Hanmei Zhao; Jianchao Qi; Chunli Li; Junjie Qi; Jiajia Guo

    2015-01-01

    The energy-conserving performance of dividing wal column (DWC) is discussed in this paper. The heat transfer through the dividing wall is considered and the results are compared with that of common heat insulation dividing wall column (HIDWC). Based on the thermodynamic analysis of heat transfer dividing wall column (HTDWC) and HIDWC, both computer simulation and experiments are employed to analyze the energy-conserving situation. Mixtures of n-hexane, n-heptane and n-octane are chosen as the example for separation. The results show that the energy consumption of HTDWC is 50.3%less than that of conventional distillation column, while it is 46.4% less than that of HIDWC. It indicates that DWC is efficient on separating three-component mixtures and HTDWC can save more energy than HIDWC. Thus it is necessary to consider the heat transfer while applying DWC to industry.

  7. Planar multijunction high voltage solar cells

    Science.gov (United States)

    Evans, J. C., Jr.; Chai, A. T.; Goradia, C.

    1980-01-01

    Technical considerations, preliminary results, and fabrication details are discussed for a family of high-voltage planar multi-junction (PMJ) solar cells which combine the attractive features of planar cells with conventional or interdigitated back contacts and the vertical multijunction (VMJ) solar cell. The PMJ solar cell is internally divided into many voltage-generating regions, called unit cells, which are internally connected in series. The key to obtaining reasonable performance from this device was the separation of top surface field regions over each active unit cell. Using existing solar cell fabricating methods, output voltages in excess of 20 volts per linear centimeter are possible. Analysis of the new device is complex, and numerous geometries are being studied which should provide substantial benefits in both normal sunlight usage as well as with concentrators.

  8. Orbital angular momentum divider of light

    CERN Document Server

    Dong, Hailong Zhou Jianji; Cai, Xinlun; Yu, SiYuan; Zhang, Xinliang

    2016-01-01

    Manipulation of orbital angular momentum (OAM) of light is essential in OAM-based optical systems. Especially, OAM divider, which can convert the incoming OAM mode into one or several new smaller modes in proportion at different spatial paths, is very useful in OAM-based optical networks. However, this useful tool was never reported yet. For the first time, we put forward a passive OAM divider based on coordinate transformation. The device consists of a Cartesian to log-polar coordinate converter and an inverse converter. The first converter converts the OAM light into a rectangular-shaped plane light with a transverse phase gradient. And the second converter converts the plane light into multiple diffracted light. The OAM of zeroth-order diffracted light is the product of the input OAM and the scaling parameter. The residual light is output from other diffracted orders. Furthermore, we extend the scheme to realize equal N-dividing of OAM and arbitrary dividing of OAM. The ability of dividing OAM shows huge p...

  9. Nonequilibrium stage modelling of dividing wall columns and experimental validation

    Science.gov (United States)

    Hiller, Christoph; Buck, Christina; Ehlers, Christoph; Fieg, Georg

    2010-11-01

    Dealing with complex process units like dividing wall columns pushes the focus on the determination of suitable modelling approaches. For this purpose a nonequilibrium stage model is developed. The successful validation is achieved by an experimental investigation of fatty alcohol mixtures under vacuum condition at pilot scale. Aim is the recovery of high purity products. The proposed model predicts the product qualities and temperature profiles very well.

  10. 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.

  11. 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

  12. Wideband unbalanced waveguide power dividers and combiners

    Energy Technology Data Exchange (ETDEWEB)

    Halligan, Matthew; McDonald, Jacob Jeremiah; Strassner, II, Bernd H.

    2016-05-17

    The various technologies presented herein relate to waveguide dividers and waveguide combiners for application in radar systems, wireless communications, etc. Waveguide dividers-combiners can be manufactured in accordance with custom dimensions, as well as in accordance with waveguide standards such that the input and output ports are of a defined dimension and have a common impedance. Various embodiments are presented which can incorporate one or more septum(s), one or more pairs of septums, an iris, an input matching region, a notch located on the input waveguide arm, waveguide arms having stepped transformer regions, etc. The various divider configurations presented herein can be utilized in high fractional bandwidth applications, e.g., a fractional bandwidth of about 30%, and RF applications in the Ka frequency band (e.g., 26.5-40 GHz).

  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. Calculation of Contactor Action Voltage Value in Different Ambient Temperature%接触器在不同工作环境温度下动作电压值的计算

    Institute of Scientific and Technical Information of China (English)

    周月英

    2011-01-01

    Introduction was made to the method of using serial resistors for calculation when AC contactor was in action performance test under special temperature.Via theory calculation for suck in and release voltage of AC contactor winding,the problem of correctl%介绍了交流接触器动作性能试验时在不同工作环境温度下,使用串联电阻计算的方法。通过对交流接触器线圈吸合和释放电压的理论计算,解决制造企业虽不具备标准要求的环境温度条件而能准确地计算出线圈的吸合和释放电压问题,帮助制造企业合理地控制产品的主要技术数据,提高产品合格率。

  15. 低频唤醒在电厂高压开关柜触头温度监测中的应用%Application of Low Frequency Wake-up in High Voltage Switchgear Contact Temperature Monitoring for Power Plants

    Institute of Scientific and Technical Information of China (English)

    周晓莉

    2014-01-01

    针对无线式电厂高压开关柜触头温度监测中无线采集模块供电不稳和系统组网问题,提出了一种无线采集模块采用高方式间歇工作的方法,降低了功耗,解决了无线发送冲突的问题。给出了系统框图,阐述了工作原理,介绍了低频唤醒方式的具体实现方法。%This paper puts forward a method of wireless picking module by batch working according to low frequency wake-up. It solves the problem of instable current supply and system network of the wireless picking module in the system of high voltage switchgear contact temperature monitoring for power plants. The method reduces the power consumption and solves the problem of the conflict of wireless transmission. It provides the system block diagram of the module and represents its working principle. At last, it offers the detailed method of the low frequency wake-up.

  16. Bridging the digital divide with mobile services

    CERN Document Server

    Yelton, Andromeda

    2013-01-01

    In this issue of Library Technology Reports, Andromeda Yelton shows how libraries can build on the breadth of this population to help bridge the digital divide and provide even greater access to information. Yelton breaks down the demographics of mobile internet users, provides examples of how different libraries are reaching out to these populations, and suggests what the future may hold for this trend.

  17. Digital divide research, achievements and shortcomings

    NARCIS (Netherlands)

    Dijk, van Jan A.G.M.

    2006-01-01

    From the end of the 1990s onwards the digital divide, commonly defined as the gap between those who have and do not have access to computers and the Internet, has been a central issue on the scholarly and political agenda of new media development. This article makes an inventory of 5 years of digita

  18. The electronic health record: a digital divide?

    Science.gov (United States)

    Glaser, John

    2007-10-01

    The gap between EHR adoption among larger providers versus adoption by smaller or rural providers has caused a "digital divide" that could threaten smaller providers' survival in the years ahead. Closing this gap will require the collective action of providers, payers, and government.

  19. Digital divide research, achievements and shortcomings

    NARCIS (Netherlands)

    van Dijk, Johannes A.G.M.

    2006-01-01

    From the end of the 1990s onwards the digital divide, commonly defined as the gap between those who have and do not have access to computers and the Internet, has been a central issue on the scholarly and political agenda of new media development. This article makes an inventory of 5 years of

  20. Young People's Internet Use: Divided or Diversified?

    Science.gov (United States)

    Boonaert, Tom; Vettenburg, Nicole

    2011-01-01

    This article critically analyses research on young people's internet use. Based on a literature analysis, it examines which young people do what on the internet. These results invite a reflection on the dominant discourse on the digital divide. Within this discourse, there is a strong focus on the use of the internet for information purposes only,…

  1. Democratisation and Conflict in Ethnically Divided Societies

    NARCIS (Netherlands)

    Vorrath, Judith; Krebs, Lutz

    2009-01-01

    This article reviews three important factors in the academic debate on ethnic civil wars: the role of ethnicity in causing and structuring violence, the spread of ethnic civil wars once they have started, and the influence of democratic transitions in divided societies. The review displays the range

  2. 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.

  3. 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.

  4. Evolution of a Voltage-Time Model of Thermal Batteries

    Science.gov (United States)

    1991-02-01

    MARK I1 VOLTAGE-TIME MODEL 7 6 MARKt III VOLTAGE-TIME MODEL 10 6.1 Capacity degradation II 6,2 Allowance ’for time-dependent polarisation If 6,3...period is sub- divided into two or more segments in the model input data, in all of which the TM MS 1163 13 same current or resistor value operates as

  5. Conquering the digital divide: Botswana and South Korea digital divide status and interventions

    Directory of Open Access Journals (Sweden)

    Nonofo C. Sedimo

    2011-03-01

    Full Text Available Background: Botswana is putting in place initiatives towards establishing itself as a knowledgebased economy. Transformation from a resource-based to a knowledge-based economy is partly hinged on innovation, research and development capability, knowledge channels, and the funding of research and development activities.Objectives: Bridging the digital divide and narrowing the intra-national divide brings about global information and communication technology (ICT usage that translates into changing work patterns and eventually transformed economies. This article outlines the different interventions implemented in Botswana to bridge the divide. The South Korean experience in bridging the divide is discussed so as to serve as lessons on how to effectively bridge the divide to Botswana’s initiatives.Method: Using a mix of exploratory and empirical study, this article presents the findings on the status of ICT uptake in Botswana and investigates the level of the digital divide in the country.Results: The results of the study show that the digital divide is much more evident in Botswana than in South Korea. South Korea has put in place robust strategic initiatives towards reducing the digital divide and this has largely transcended into its transformation into a full-fledged knowledge society.Conclusion: This article is timely as it unearths the different pointers that may be utilised in policy formation and what interventions need to be taken at both the individual and national level to bridge the digital divide.

  6. Analyzing Broadband Divide in the Farming Sector

    DEFF Research Database (Denmark)

    Jensen, Michael; Gutierrez Lopez, Jose Manuel; Pedersen, Jens Myrup

    2013-01-01

    Agriculture industry has been evolving for centuries. Currently, the technological development of Internet oriented farming tools allows to increase the productivity and efficiency of this sector. Many of the already available tools and applications require high bandwidth in both directions......, upstream and downstream connection. The main constraint is that farms are naturally located in rural areas where the required access broadband data rates are not available. This paper studies the broadband divide in relation to the Danish agricultural sector. Results show how there is an important...... difference between the broadband availability for farms and the rest of the households/buildings the country. This divide may be slowing down the potential technological development of the farming industry, in order to keep their competitiveness in the market. Therefore, broadband development in rural areas...

  7. Divided or kissing nevus of the penis.

    Science.gov (United States)

    Hardin, Carolyn A; Tieu, Kathy D

    2013-10-16

    The divided or kissing nevus is an unusual congenital melanocytic nevus. By definition, these nevi appear on skin that separates during embryological development. These lesions have been reported on the eyelids, fingers, and rarely the penis. We describe an 18 year old uncircumcised male who presented with an asymptomatic darkly pigmented patch on the glans penis. He reported that the lesion had appeared recently and was enlarging. Physical examination revealed a second symmetric lesion on the adjacent foreskin. Punch biopsy of the lesion on the glans penis showed abundant intradermal melanocytes devoid of mitoses and atypia, consistent with an intradermal melanocytic nevus. Based on the benign histologic nature and clinical exam, the lesion was diagnosed as a divided or kissing nevus of the penis. Proposed treatments include excision and grafting as well as Nd:YAG laser therapy. However, these patients may be safely monitored with regular follow-up skin examinations because there is minimal risk of malignant transformation.

  8. 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.

  9. Divided libraries remodeling management to unify institutions

    CERN Document Server

    Webb, TD

    2012-01-01

    Given the highly trained library workforce now available and the vast and growing array of packaging information and knowledge, libraries have the capacity to become pre-eminent places of learning, research, and teaching. Yet, despite this potential, libraries remain divided from their constituencies and their governing bodies, be they students, faculties, university administrations, municipal governments, or ordinary citizens. Indeed, many modern university administrators, viewing librarians as ancillary citizens in academe, have allowed their libraries to wither under the burden of shrinking

  10. Nursing's divided loyalties: an historical case study.

    Science.gov (United States)

    Baer, E D

    1989-01-01

    Using the historical version of the case study method, this research explored an example of turn-of-the-century nurses' conflicted loyalties. One training school alumnae association was examined to demonstrate that nurses acted out simultaneous loyalty to competing entities: individual graduates attributes vs. associational eligibility requirements; member vs. institutions' needs; and local vs. national nursing concerns. As a result of these divided loyalties, the nurses did not meet the alumnae organizational goals they set for themselves.

  11. Parametric frequency dividers in satellite communications

    OpenAIRE

    Kosmopoulos, S. A.; Lo Forti, R.; Saggese, E.

    1990-01-01

    The performance of two different parametric frequency dividers, using GaAs varactor diodes in a balanced circuit configuration implemented by planar (microstrip) or quasi-planar (finline, coupled finline ) elements respectively, is presented. The almost phase noise free operation of these devices allows the construction of efficient miniature synthesizers or carrier recovering schemes, incorporated on the space segment of Ku- or Ka-band satellite communications systems.

  12. Self-organization of divided hierarchy

    Science.gov (United States)

    Odagaki, Takashi; Kitada, Keigo; Omizo, Kenta; Fujie, Ryo

    2015-03-01

    There are two types of extreme form of hierarchy, one is the plutonomy where small fraction of winners and losers and many people in the middle class appear and the other a divided hierarchy where half of population become winners and the remaining half become losers. We study the emergence of the divided hierarchy in a model society which consists of bellicose individuals who always try to fight and fight with the strongest neighbor and pacific individuals who always try not to fight and when necessary fight with the weakest neighbor. In our model society, (1) individuals make random walk on a square lattice, (2) when two individuals encounter they fight each other and (3) the winner deprives wealth from the loser. By a Monte Carlo simulation, we show that there are two transitions when the population density is increased; one is a transition from the egalitarian society to a hierarchical society I where winners, losers and middle classes coexist and the other is a transition from the hierarchical society I to a hierarchical society II where winners and losers exist but no middle classes exist, that is the divided hierarchy. We also show that clusters consisting mostly of bellicose individuals appear in the hierarchical society I.

  13. 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.

  14. Splicing the Divide: A Review of Research on the Evolving Digital Divide among K-12 Students

    Science.gov (United States)

    Dolan, Jennifer E.

    2016-01-01

    The digital divide has narrowed with regard to one definition of access to technology--the binary view of the "haves" and "have-nots." However, use of technology at home and in school is not equitable for all students. According to recent literature, a broader and more nuanced definition of the technological divide is necessary…

  15. SIW based multilayer transition and power divider in LTCC technology

    KAUST Repository

    Abuzaid, Hattan

    2013-06-01

    A multilayer transition and balanced power divider are presented for millimeter-wave system-on-package (SoP). These two components operate at Ka-band and exploit the substrate integrate waveguide (SIW) technology with its shielding characteristics and the Low-temperature co-fired ceramics (LTCC) technology for its high density integration. A coupling slot has been used to perform vertical integration, which can be easily optimized through its length. The measured input return loss within the bandwidth of interest (32 GHz-38 GHz) is less than -15 dB and -18 dB for the multilayer transition and the power divider, respectively. The lateral dimensions of a multilayer system, such as a feed network of an array, can be greatly reduced by employing these 3D slot-coupled components. © 2013 IEEE.

  16. The plastid-dividing machinery: formation, constriction and fission.

    Science.gov (United States)

    Yoshida, Yamato; Miyagishima, Shin-ya; Kuroiwa, Haruko; Kuroiwa, Tsuneyoshi

    2012-12-01

    Plastids divide by constriction of the plastid-dividing (PD) machinery, which encircles the division site. The PD machinery consists of the stromal inner machinery which includes the inner PD and filamenting temperature-sensitive mutant Z (FtsZ) rings and the cytosolic outer machinery which includes the outer PD and dynamin rings. The major constituent of the PD machinery is the outer PD ring, which consists of a bundle of polyglucan filaments. In addition, recent proteomic studies suggest that the PD machinery contains additional proteins that have not been characterized. The PD machinery forms from the inside to the outside of the plastid. The constriction seems to occur by sliding of the polyglucan filaments of the outer PD ring, aided by dynamin. The final fission of the plastid is probably promoted by the 'pinchase' activity of dynamin.

  17. Influence of stator ventilation channel on the temperature field in the middle-size high voltage motor%定子通风槽钢对中型高压电机内温度场的影响

    Institute of Scientific and Technical Information of China (English)

    温嘉斌; 侯健; 于喜伟

    2016-01-01

    According to the structural dimensions of the motor,a YKK450-4,500 kW medium high-voltage asynchronous motor is taken as an example to construct the 3D mathematical model and physical model of stator and rotor radial ventilation ducts with the adjacent core segment of the high voltage asynchronous motor.Based on the theoretical knowledge of fluid mechanics and heat transfer,assumptions and boundary conditions were given to conduct calculation of the simulation,and the temperature field of the calculated region were analyzed.Finally, under the condition that the length of the ventilation channel of the stator remained unchanged,and the radial position near the shaft of the stator ventilation channel was changed, the model of ventilation dutcs was remodeled to obtain the influence of the installation position of the sta-tor ventilation channel on the temperature field in motor.The results show that radial position of the venti-lation channel affects the cooling effect of the stator windings, which provides a theoretical basis to im-prove the thermal dissipation performance of the motor and the optimization design of the motor ventilation structure.%该研究以一台YKK450-4、500 kW中型高压异步电动机为例,结合电机的结构尺寸,建立了高压异步电机三维定转子径向通风沟以及与之相邻铁心段的流体与固体耦合数学模型和物理模型;基于流体力学和传热学的理论知识,给出假设条件和边界条件,进行仿真计算,分析了计算区域的温度场;最后在定子通风槽钢长度不变的基础上,改变定子通风槽钢近轴端的径向位置,对通风沟进行重新建模,得到定子通风槽钢近轴端的径向位置对电机内温度场的影响。计算结果表明,通风槽钢的径向位置影响定子绕组的冷却效果。研究结果为提高电机的散热性能,对电机进行通风结构的优化设计提供了理论依据。

  18. 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...

  19. 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.

  20. 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…

  1. 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.

  2. The private – public law divide

    DEFF Research Database (Denmark)

    Gyldenløve Jeppesen-de Boer, Christina; Kronborg, Annette; Svendsen, Idamarie Leth

    2013-01-01

    to a particular societal institution. Marriage as an institution has been individualized and the goodness of the family has to relate to the well-being of the individuals instead. This article shows that within this historical development the private-public law divide has not been seriously challenged......In a Scandinavian perspective, the family and the individual have changed places during the 20th Century. Today, the law takes its starting point in the individual - not in the family. A consequence of this development is that it is no longer legally possible to relate the good family...

  3. CMOS Direct-Injection Divide-by-3 Injection-Locked Frequency Dividers

    Institute of Scientific and Technical Information of China (English)

    Chia-Wei; Chang; Jhin-Fang; Huang; Sheng-Lyang; Jang; Ying-Hsiang; Liao; Miin-Horng; Juang

    2010-01-01

    <正>This paper proposes CMOS LC-tank divide-by-3 injection locked frequency dividers(ILFDs)fabricated in 0.18μn and 90nm CMOS process and describes the circuit design,operation principle and measurement results of the ILFDs.The ILFDs use two injection series-MOSFETs across the LC resonator and a differential injection signal is applied to the gates of injection MOSFETs.The direct-injection divide-by-3 ILFDs are potential for radio-frequency application and can have wide locking range.

  4. Alternating current breakdown voltage of ice electret

    Science.gov (United States)

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

    2017-09-01

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

  5. America's digital divide: 2000-2003 trends.

    Science.gov (United States)

    Whaley, Kermit C

    2004-04-01

    Computer ownership and literacy, along with Internet access and its many applications, has become, for many, a trademark for the Americans' lifestyle. Research shows that computer ownership and literacy, along with Internet access and expertise, is rapidly changing how Americans go about their business. The technological industry is providing many opportunities for Americans to operate in markets, global and local, not previously available. These changes are apparent across all U.S. sociocultural and geographic boundaries. Yet, upon close analysis, there are individuals and communities less connected with many completely excluded from participation. Those individuals exist below a line called the Digital Divide. Growth in computer ownership and Internet use, while offering optimism that the Digital Divide is narrowing, also illustrates that, without focused intervention will for certain populations, continue. Public and private programs, focus groups, and pocks of community activism, each hope to correct the disparities among on- and-off line Americans. On many fronts, there is evidence that progress is being made by many. Income, race, age, and geographic location are often the determining factors.

  6. Media Literacy in Times of Media Divides

    Directory of Open Access Journals (Sweden)

    Kaja Žuran

    2013-12-01

    Full Text Available We live in a post-modern society, an information society, a society based around knowledge and participation, and above all in a media society. In a media culture where media holds a dominant position, we cannot overlook the emerging idea of a ‘media divide’ within the frame of media education, media literate individuals and the expansion of the traditional concept of media literacy. Firstly, we are in an era of technological revolution, and it is time to consider the meaning and function of media and how we experience it in our everyday life. Secondly, as a society we are subject to intense media invasion and we all need to learn how to use it to our benefit and apply a critical and autonomous perspective towards selecting media content. Otherwise the media divide between the media literate and illiterate will widen; but is there even a chance to overcome the supposed divide between those who are formally media educated and those who are not?

  7. 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.

  8. Universal logic gates via liquid-electronic hybrid divider

    KAUST Repository

    Zhou, Bingpu

    2012-01-01

    We demonstrated two-input microdroplet-based universal logic gates using a liquid-electronic hybrid divider. All 16 Boolean logic functions have been realized by manipulating the applied voltages. The novel platform consists of a microfluidic chip with integrated microdroplet detectors and external electronic components. The microdroplet detectors act as the communication media for fluidic and electronic information exchange. The presence or absence of microdroplets at the detector translates into the binary signal 1 or 0. The embedded micro-mechanical pneumatically actuated valve (PAV), fabricated using the well-developed multilayer soft lithography technique, offers biocompatibility, flexibility and accuracy for the on-chip realization of different logic functions. The microfluidic chip can be scaled up to construct large-scale microfluidic logic computation. On the other hand, the microfluidic chip with a specific logic function can be applied to droplet-based chemical reactions for on-demand bio or chemical analysis. Our experimental results have presented an autonomously driven, precision-controlled microfluidic chip for chemical reactions based on the IF logic function. © 2012 The Royal Society of Chemistry.

  9. 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.

  10. 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.

  11. Planar LTCC transformers for high voltage flyback converters.

    Energy Technology Data Exchange (ETDEWEB)

    Schofield, Daryl (NASCENT Technology Inc. , Watertown, SD); Schare, Joshua M.; Glass, Sarah Jill; Roesler, Alexander William; Ewsuk, Kevin Gregory; Slama, George (NASCENT Technology Inc. , Watertown, SD); Abel, Dave (NASCENT Technology Inc. , Watertown, SD)

    2007-06-01

    This paper discusses the design and use of low-temperature (850 C to 950 C) co-fired ceramic (LTCC) planar magnetic flyback transformers for applications that require conversion of a low voltage to high voltage (> 100V) with significant volumetric constraints. Measured performance and modeling results for multiple designs showed that the LTCC flyback transformer design and construction imposes serious limitations on the achievable coupling and significantly impacts the transformer performance and output voltage. This paper discusses the impact of various design factors that can provide improved performance by increasing transformer coupling and output voltage. The experiments performed on prototype units demonstrated LTCC transformer designs capable of greater than 2 kV output. Finally, the work investigated the effect of the LTCC microstructure on transformer insulation. Although this paper focuses on generating voltages in the kV range, the experimental characterization and discussion presented in this work applies to designs requiring lower voltage.

  12. 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.

  13. 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

  14. Optical voltage sensors: principle, problem and research proposal

    Science.gov (United States)

    Li, Changsheng

    2016-10-01

    Sensing principles and main problems to be solved for optical voltage sensors are briefly reviewed. Optical effects used for voltage sensing usually include electro-optic Pockels and Kerr effects, electro-gyration effect, elasto-optical effect, and electroluminescent effects, etc. In principle, typical optical voltage sensor is based on electro-optic Pockels crystals and closed-loop signal detection scheme. Main problems to be solved for optical voltage sensors include: how to remove influence of unwanted multiple optical effects on voltage sensing performance; how to select or develop a proper voltage sensing material and element; how to keep optical phase bias to be stable under temperature fluctuation and vibration; how to achieve dc voltage sensing, etc. In order to suppress the influence of unwanted optical effects and light beam coupling-related loss on voltage sensing signals, we may pay more attention to all-fiber and waveguide voltage sensors. Voltage sensors based on electroluminescent effects are also promising in some application fields due to their compact configuration, low cost and potential long-term reliability.

  15. DIGITAL DIVIDE IN THE EUROPEAN UNION

    Directory of Open Access Journals (Sweden)

    Radu HERMAN

    2009-10-01

    Full Text Available This paper aims to demonstrate that income, education and infrastructure play a critical role in shaping the divide. The global challenge for the new millennium is to build a society where everyone can access and shareinformation. A fully integrated digital world has become a reality, and all segments of society must embrace it in order to be contributing partners to future success in the EU. As they are fast becoming an essential tool for economic activity, Information and Communication Technologies (ICT became a vital engine of economic performance. The problem, however, is that in many countries technological diffusion is obstructed by the limited capacity of networks to carry large amounts of knowledge swiftly and the limited access of individuals even to networks in which knowledge products are minimal.

  16. Library outreach: addressing Utah's "Digital Divide".

    Science.gov (United States)

    McCloskey, K M

    2000-10-01

    A "Digital Divide" in information and technological literacy exists in Utah between small hospitals and clinics in rural areas and the larger health care institutions in the major urban area of the state. The goals of the outreach program of the Spencer S. Eccles Health Sciences Library at the University of Utah address solutions to this disparity in partnership with the National Network of Libraries of Medicine-- Midcontinental Region, the Utah Department of Health, and the Utah Area Health Education Centers. In a circuit-rider approach, an outreach librarian offers classes and demonstrations throughout the state that teach information-access skills to health professionals. Provision of traditional library services to unaffiliated health professionals is integrated into the library's daily workload as a component of the outreach program. The paper describes the history, methodology, administration, funding, impact, and results of the program.

  17. Charge carrier transport in Cu(In,Ga)Se{sub 2} thin-film solar-cells studied by electron beam induced current and temperature and illumination dependent current voltage analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nichterwitz, Melanie

    2012-01-10

    This work contributes to the understanding of generation dependent charge-carrier transport properties in Cu(In,Ga)Se{sub 2} (CIGSe)/ CdS/ ZnO solar cells and a consistent model for the electronic band diagram of the heterojunction region of the device is developed. Cross section electron-beam induced current (EBIC) and temperature and illumination dependent current voltage (IV) measurements are performed on CIGSe solar cells with varying absorber layer compositions and CdS thickness. For a better understanding of possibilities and limitations of EBIC measurements applied on CIGSe solar cells, detailed numerical simulations of cross section EBIC profiles for varying electron beam and solar cell parameters are performed and compared to profiles obtained from an analytical description. Especially the effects of high injection conditions are considered. Even though the collection function of the solar cell is not independent of the generation function of the electron beam, the local electron diffusion length in CIGSe can still be extracted. Grain specific values ranging from (480±70) nm to (2.3±0.2) μm are determined for a CuInSe{sub 2} absorber layer and a value of (2.8±0.3) μm for CIGSe with a Ga-content of 0.3. There are several models discussed in literature to explain generation dependent charge carrier transport, all assuming a high acceptor density either located in the CIGSe layer close to the CIGSe/CdS interface (p{sup +} layer), within the CdS layer or at the CdS/ZnO interface. In all models, a change in charge carrier collection properties is caused by a generation dependent occupation probability of the acceptor type defect state and the resulting potential distribution throughout the device. Numerical simulations of EBIC and IV data are performed with parameters according to these models. The model that explains the experimental data best is that of a p{sup +} layer at the CIGSe/CdS interface and acceptor type defect states at the CdS/ZnO interface

  18. A new level-shifting structure with multiply metal rings by divided RESURF technique

    Institute of Scientific and Technical Information of China (English)

    Liu Jizhi; Chen Xingbi

    2009-01-01

    A new structure of a lateral n-MOST and a new level-shifting structure with multiply metal rings(MMRs) by divided RESURF technique have been proposed.The device and electrical performances of the structure are analyzed and simulated by MEDICI.In comparison to the level-shifting structure with multiply floating field plates (MFFPs)used before,the structure stated here improves the reliability and diminishes the voltage difference between the voltage of the power supply of the high-side gate driver and the voltage of the output terminal of the level-shifting structure,which is also that of the input terminal of the high-side gate driver.The maximal voltage difference of the level-shifting structure in this paper is 30%lower than that used before.Therefore,good voltage isolation and current isolation are obtained.The structure can be used in the level-shifting circuit of various applications.

  19. 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....

  20. 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...

  1. 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.

  2. Infrared Fiber-Optical Temperature Sensor.

    Science.gov (United States)

    where they are amplified by the electronics. A voltage is then outputted which represents measured temperature. The voltage is sampled by the computer where it is converted to temperature by use of computer algorithms .

  3. 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.

  4. High-Voltage, Low-Power BNC Feedthrough Terminator

    Science.gov (United States)

    Bearden, Douglas

    2012-01-01

    This innovation is a high-voltage, lowpower BNC (Bayonet Neill-Concelman) feedthrough that enables the user to terminate an instrumentation cable properly while connected to a high voltage, without the use of a voltage divider. This feedthrough is low power, which will not load the source, and will properly terminate the instrumentation cable to the instrumentation, even if the cable impedance is not constant. The Space Shuttle Program had a requirement to measure voltage transients on the orbiter bus through the Ground Lightning Measurement System (GLMS). This measurement has a bandwidth requirement of 1 MHz. The GLMS voltage measurement is connected to the orbiter through a DC panel. The DC panel is connected to the bus through a nonuniform cable that is approximately 75 ft (approximately equal to 23 m) long. A 15-ft (approximately equal to 5-m), 50-ohm triaxial cable is connected between the DC panel and the digitizer. Based on calculations and simulations, cable resonances and reflections due to mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. A voltage divider at the DC panel, and terminating the 50-ohm cable properly, would eliminate this issue. Due to implementation issues, an alternative design was needed to terminate the cable properly without the use of a voltage divider. Analysis shows how the cable resonances and reflections due to the mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. After simulating a dampening circuit located at the digitizer, simulations were performed to show how the cable resonances were dampened and the accuracy was improved significantly. Test cables built to verify simulations were accurate. Since the dampening circuit is low power, it can be packaged in a BNC feedthrough.

  5. Bridging the divide between science and journalism.

    Science.gov (United States)

    Van Eperen, Laura; Marincola, Francesco M; Strohm, Jennifer

    2010-03-10

    There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media.Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings.

  6. New Frontiers in the Digital Divide

    DEFF Research Database (Denmark)

    Jæger, Birgit

    In a new strategy for e-government, the Danish government set the goal that in 2015 all contacts between citizens and public authorities must be conducted electronically. In accordance with EU’s strategy for e-government every citizen ought to have equal access to public services, hence the quest......In a new strategy for e-government, the Danish government set the goal that in 2015 all contacts between citizens and public authorities must be conducted electronically. In accordance with EU’s strategy for e-government every citizen ought to have equal access to public services, hence...... for digital inclusion becomes a central theme for the implementation of the new e-government strategy. Until now it has been voluntary whether or not citizens want to use ICT and a lot of especially senior citizens have chosen not to use the technology. However, senior citizens are not the only group affected...... of the e-government strategy. New frontiers in the digital divide are opening and a new group of excluded become visible: the youngsters. In this way, one of the leading Danish newspapers reports that young people lines up in town halls to get help to fill out forms, which are already available...

  7. The Digital Divide and urban older adults.

    Science.gov (United States)

    Cresci, M Kay; Yarandi, Hossein N; Morrell, Roger W

    2010-01-01

    Computers and the Internet offer older adults opportunities and resources for independent living. However, many urban older adults do not use computers. This study examined the demographic, health, and social activities of urban older adults to determine variables that might predict the use and nonuse of computers in this population. A secondary data analysis was performed using the 2001 Detroit City-Wide Needs Assessment of Older Adults (n = 1410) data set. Logistic regression was used to explore potential differences in predictor variables between computer users and nonusers. Overall, computer users were younger (27%), had a higher level of education, were more likely to be employed, had an annual income greater than $20,000, and were healthier and more active than nonusers. They also were more likely to have memberships in community organizations and do volunteer work. Preferred computer activities included conducting Internet searches, playing games, writing, and communicating with family members and friends. The results suggest significant differences in demographic and health-related characteristics between computer users and nonusers among urban older adults. Although about a quarter of participants in this study used computers, the Digital Divide continues to exist in urban settings for scores of others.

  8. Bridging the digital divide: reaching vulnerable populations.

    Science.gov (United States)

    Chang, Betty L; Bakken, Suzanne; Brown, S Scott; Houston, Thomas K; Kreps, Gary L; Kukafka, Rita; Safran, Charles; Stavri, P Zoe

    2004-01-01

    The AMIA 2003 Spring Congress entitled "Bridging the Digital Divide: Informatics and Vulnerable Populations" convened 178 experts including medical informaticians, health care professionals, government leaders, policy makers, researchers, health care industry leaders, consumer advocates, and others specializing in health care provision to underserved populations. The primary objective of this working congress was to develop a framework for a national agenda in information and communication technology to enhance the health and health care of underserved populations. Discussions during four tracks addressed issues and trends in information and communication technologies for underserved populations, strategies learned from successful programs, evaluation methodologies for measuring the impact of informatics, and dissemination of information for replication of successful programs. Each track addressed current status, ideal state, barriers, strategies, and recommendations. Recommendations of the breakout sessions were summarized under the overarching themes of Policy, Funding, Research, and Education and Training. The general recommendations emphasized four key themes: revision in payment and reimbursement policies, integration of health care standards, partnerships as the key to success, and broad dissemination of findings including specific feedback to target populations and other key stakeholders.

  9. The Gender Digital Divide in Developing Countries

    Directory of Open Access Journals (Sweden)

    Amy Antonio

    2014-10-01

    Full Text Available Empirical studies clearly show that women in the developing world have significantly lower technology participation rates than men; a result of entrenched socio-cultural attitudes about the role of women in society. However, as studies are beginning to show, when those women are able to engage with Internet technology, a wide range of personal, family and community benefits become possible. The key to these benefits is on-line education, the access to which sets up a positive feedback loop. This review gives an overview of the digital divide, before focusing specifically on the challenges women in developing countries face in accessing the Internet. Current gender disparities in Internet use will be outlined and the barriers that potentially hinder women’s access and participation in the online world will be considered. We will then look at the potential opportunities for women’s participation in a global digital society along with a consideration of current initiatives that have been developed to mitigate gender inequity in developing countries. We will also consider a promising avenue for future research.

  10. Quantitative Measurement of the Digital Divide

    Science.gov (United States)

    Cottrell, Roger

    2007-04-01

    Bandwidth and the Internet infrastructure are the life-blood of the world's knowledge economy, but they are often scarcest where most needed. Measuring the numbers of users of the Internet infrastructure is not easy in developing countries because many people share accounts, use corporate and academic networks, or visit the rapidly growing number of cyber cafes, telecentres and business services. Also measuring the number of users does not take into account the level of use. One valuable indicator for measuring the Internet infrastructure is the international Internet performance of a country or region. One of the major aims of the PingER project is to provide an historical archive of extensive, publicly accessible, up-to-date, measurements, analyses and reports of multiple Internet performance indicators (such as delay, loss, throughput, reachability, and jitter) between sites, countries and regions of the world. This talk will briefly describe the PingER project and then compare and contrast the Internet performance and its trends within and between countries and regions of the world. By means of extensive case studies it will also identify which regions need the greatest attention, together with their major issues and possible approaches to reducing the divide.

  11. Vegetation baseline report : Connacher great divide project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-08-01

    This baseline report supported an application by Connacher Oil and Gas Ltd. to the Alberta Energy and Utilities Board (EUB) and Alberta Environment (AENV) for the Great Divide Steam Assisted Gravity Drainage (SAGD) Project. The goal of the report was to document the distribution and occurrence of ecosite phases and wetland classes in the project footprint as well as to document the distribution of rare plants; rare plant communities: and intrusive species and old growth communities, including species of management concern. A methodology of the baseline report was presented, including details of mapping and field surveys. Six vegetation types in addition to the disturbed land unit were identified in the project footprint and associated buffer. It was noted that all vegetation types are common for the boreal forest natural regions. Several species of management concern were identified during the spring rare plant survey, including rare bryophytes and non-native or invasive species. Mitigation was identified through a slight shift of the footprint, transplant of appropriate bryophyte species and implementation of a weed management plan. It was noted that results of future surveys for rare plants will be submitted upon completion. It was concluded that the effects of the project on existing vegetation is expected to be low because of the small footprint, prior disturbance history, available mitigation measures and conservation and reclamation planning. 27 refs., 5 tabs., 4 figs.

  12. Bridging the Divide between Science and Journalism

    Directory of Open Access Journals (Sweden)

    Marincola Francesco M

    2010-03-01

    Full Text Available Abstract There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media. Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings.

  13. 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.

  14. 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

  15. 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...

  16. Research and Experiments on a Unipolar Capacitive Voltage Sensor

    Directory of Open Access Journals (Sweden)

    Qiang Zhou

    2015-08-01

    Full Text Available Voltage sensors are an important part of the electric system. In service, traditional voltage sensors need to directly contact a high-voltage charged body. Sensors involve a large volume, complex insulation structures, and high design costs. Typically an iron core structure is adopted. As a result, ferromagnetic resonance can occur easily during practical application. Moreover, owing to the multilevel capacitor divider, the sensor cannot reflect the changes of measured voltage in time. Based on the electric field coupling principle, this paper designs a new voltage sensor; the unipolar structure design solves many problems of traditional voltage sensors like the great insulation design difficulty and high costs caused by grounding electrodes. A differential signal input structure is adopted for the detection circuit, which effectively restrains the influence of the common-mode interference signal. Through sensor modeling, simulation and calculations, the structural design of the sensor electrode was optimized, miniaturization of the sensor was realized, the voltage division ratio of the sensor was enhanced, and the phase difference of sensor measurement was weakened. The voltage sensor is applied to a single-phase voltage class line of 10 kV for testing. According to the test results, the designed sensor is able to meet the requirements of accurate and real-time measurement for voltage of the charged conductor as well as to provide a new method for electricity larceny prevention and on-line monitoring of the power grid in an electric system. Therefore, it can satisfy the development demands of the smart power grid.

  17. Low voltage bandgap reference with closed loop curvature compensation

    Science.gov (United States)

    Tao, Fan; Bo, Du; Zheng, Zhang; Guoshun, Yuan

    2009-03-01

    A new low-voltage CMOS bandgap reference (BGR) that achieves high temperature stability is proposed. It feeds back the output voltage to the curvature compensation circuit that constitutes a closed loop circuit to cancel the logarithmic term of voltage VBE. Meanwhile a low voltage amplifier with the 0.5 μm low threshold technology is designed for the BGR. A high temperature stability BGR circuit is fabricated in the CSMC 0.5 μm CMOS technology. The measured result shows that the BGR can operate down to 1 V, while the temperature coefficient and line regulation are only 9 ppm/°C and 1.2 mV/V, respectively.

  18. Low voltage bandgap reference with closed loop curvature compensation

    Institute of Scientific and Technical Information of China (English)

    Fan Tao; Du Bo; Zhang Zheng; Yuan Guoshun

    2009-01-01

    A new low-voltage CMOS bandgap reference (BGR) that achieves high temperature stability is proposed. It feeds back the output voltage to the curvature compensation circuit that constitutes a closed loop circuit to cancel the logarithmic term of voltage VBE. Meanwhile a low voltage amplifier with the 0.5μm low threshold technology is designed for the BGR. A high temperature stability BGR circuit is fabricated in the CSMC 0.5μm CMOS tech-nology. The measured result shows that the BGR can operate down to 1 V, while the temperature coefficient and line regulation are only 9 ppm/℃ and 1.2 mV/V, respectively.

  19. Voltage-Gated Channels as Causative Agents for Epilepsies

    Directory of Open Access Journals (Sweden)

    Mutasem Abuhamed

    2008-01-01

    Full Text Available Problem statement: Epilepsy is a common neurological disorder that afflicts 1-2% of the general population worldwide. It encompasses a variety of disorders with seizures. Approach: Idiopathic epilepsies were defined as a heterogeneous group of seizure disorders that show no underlying cause .Voltage-gated ion channels defect were recognized etiology of epilepsy in the central nervous system. The aim of this article was to provide an update on voltage-gated channels and their mutation as causative agents for epilepsies. We described the structures of the voltage-gated channels, discuss their current genetic studies, and then review the effects of voltage-gated channels as causative agents for epilepsies. Results: Channels control the flow of ions in and out of the cell causing depolarization and hyper polarization of the cell. Voltage-gated channels were classified into four types: Sodium, potassium calcium ands chloride. Voltage-gated channels were macromolecular protein complexes within the lipid membrane. They were divided into subunits. Each subunit had a specific function and was encoded by more than one gen. Conclusion: Current genetic studies of idiopathic epilepsies show the importance of genetic influence on Voltage-gated channels. Different genes may regulate a function in a channel; the channel defect was directly responsible for neuronal hyper excitability and seizures.

  20. 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...

  1. 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.

  2. 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.

  3. "Enlivening and - Dividing": An Aporia of Illumination

    Directory of Open Access Journals (Sweden)

    Hans Christian Hönes

    2015-08-01

    Full Text Available Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Verdana;} In 1798, Karl August Böttiger paid a nocturnal visit to the Gallery of Antiques in Dresden, illuminating the statues with a torch. At first glance, this seems to be yet another example of a popular practice for visiting galleries c.1800. Illuminating the sculptures by torchlight was a popular means of enlivening the objects, set in motion by the light flickering on their surfaces. The collections were thus meant to become a place where cold, white stone comes to life, and where the beholder becomes part of a revived antiquity.This was precisely what Böttiger intended, too. But to him, the effect of the torchlight appeared to be, as he wrote, “enlivening and – dividing!” The torchlight highlighted not only the beauty of the sculptures but also their modern restorations. Böttiger apparently failed to experience the living presence of the antique celebrated by many of his contemporaries (e.g. Goethe, Moritz.This essay focuses on the consequence of such a perception of sculptures as historically multi-layered objects. Böttiger’s experience resulted in a problematic situation. In trying to view the sculptures as contemporaries, he hoped to become ancient himself. But this operation failed in the moment when the sculptures themselves appeared to be anachronistic, impure palimpsests. In consequence, galleries may not only be the place were art history as chronological Stilgeschichte was born. They may also be the site where this perception changed into the experience of a more chaotic shape of time.

  4. 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.

  5. Divided-pulse nonlinear amplification and simultaneous compression

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Qiang; Zhang, Qingshan; Sun, Tingting; Chen, Jie; Wang, Yuqing; Guo, Zhengru; Yang, Kangwen [Shanghai Key Laboratory of Modern Optical System, and Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Guo, Zhanhua [Shanghai Langyan Optoelectronic Science and Technology Co., LTD, Shanghai 200433 (China); Zeng, Heping, E-mail: hpzeng@phy.ecnu.edu.cn [Shanghai Key Laboratory of Modern Optical System, and Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China)

    2015-03-09

    We report on a fiber laser system delivering 122 fs pulse duration and 600 mW average power at 1560 nm by the interplay between divided pulse amplification and nonlinear pulse compression. A small-core double-clad erbium-doped fiber with anomalous dispersion carries out the pulse amplification and simultaneously compresses the laser pulses such that a separate compressor is no longer necessary. A numeric simulation reveals the existence of an optimum fiber length for producing transform-limited pulses. Furthermore, frequency doubling to 780 nm with 240 mW average power and 98 fs pulse duration is achieved by using a periodically poled lithium niobate crystal at room temperature.

  6. Characteristics and Breakdown Behaviors of Polysilicon Resistors for High Voltage Applications

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Tang

    2015-01-01

    Full Text Available With the rapid development of the power integrated circuit technology, polysilicon resistors have been widely used not only in traditional CMOS circuits, but also in the high voltage applications. However, there have been few detailed reports about the polysilicon resistors’ characteristics, like voltage and temperature coefficients and breakdown behaviors which are critical parameters of high voltage applications. In this study, we experimentally find that the resistance of the polysilicon resistor with a relatively low doping concentration shows negative voltage and temperature coefficients, while that of the polysilicon resistor with a high doping concentration has positive voltage and temperature coefficients. Moreover, from the experimental results of breakdown voltages of the polysilicon resistors, it could be deduced that the breakdown of polysilicon resistors is thermally rather than electrically induced. We also proposed to add an N-type well underneath the oxide to increase the breakdown voltage in the vertical direction when the substrate is P-type doped.

  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. 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.

  9. Combined method for simultaneously dewatering and reconstituting finely divided carbonaceous material

    Science.gov (United States)

    Wen, Wu-Wey; Deurbrouck, Albert W.

    1990-01-01

    A finely-divided carbonaceous material is dewatered and reconstituted in a combined process by adding a binding agent directly into slurry of finely divided material and dewatering the material to form a cake or consolidated piece which can be hardened by drying at ambient or elevated temperatures. Alternatively, the binder often in the form of a crusting agent is sprayed onto the surface of a moist cake prior to curing.

  10. Statistical and numerical methods to improve the transient divided bar method

    DEFF Research Database (Denmark)

    Bording, Thue Sylvester; Nielsen, S.B.; Balling, N.

    The divided bar method is a commonly used method to measure thermal conductivity of rock samples in laboratory. We present improvements to this method that allows for simultaneous measurements of both thermal conductivity and thermal diffusivity. The divided bar setup is run in a transient mode a...... and the temperature distribution in the stack is simulated by Finite Element Modeling (FEM). A Markov Chain Monte Carlo Metropolis Hastings (MCMCMH) algorithm is used to estimate the thermal parameters of the sample....

  11. 正弦高压驱动的氩等离子体射流长度和温度特性的研究∗%Investigation on the Length and Temperature of an Ar Plasma Jet Driven by Sinusoidal High Voltage

    Institute of Scientific and Technical Information of China (English)

    俞永波; 杨兰兰; 屠彦; 户玎岚

    2015-01-01

    大气压低温等离子体射流的长度和温度是射流的两个重要的参数,利用10kHz的正弦高压驱动在大气环境中产生了稳定的Ar等离子体射流,并对射流的长度特性和温度特性进行了研究。研究发现射流的长度随着外加电压的增加而增加,随着气流速率的增加先增加,到达一定值后又逐渐减小。利用光纤温度计和光谱仪测量并计算了射流的宏观温度以及电子激发温度,发现射流的宏观温度接近室温,而电子激发温度均小于1.5×104 K,基本属于冷等离子体范畴,并且它们均随着外加电压的增加而增加。%Length and temperature are two important parameters of the atmospheric plasma jet. An argon plasma jet has been generated in the atmospheric environment driven by 10 kHz sinusoidal high voltage. The length and tem-perature of the plasma jet were measured by the optical and electrical instruments. The results show that the length of the plasma jet increases with the applied voltage,but first increases with the flow rate and then decreases gradual-ly with a further increase of the flow rate. The jet temperature and the electron excited temperature were measured and calculated by the optical fiber thermometer and spectrometer. The jet temperature is closed to the room tempera-ture and the electron excited temperature is less than 1.5×104 K,which is among the range of the cold plasma. Mo-reover,both of them rise with the voltage increasing.

  12. Low voltage varistor ceramics based on SnO2

    Indian Academy of Sciences (India)

    S R Dhage; V Ravi; O B Yang

    2007-12-01

    The nonlinear current ()–voltage () characteristics of tin dioxide doped with either Nb2O5 and CoO or Sb2O3 and CoO show promising values of nonlinear coefficient () values (∼11) with low breakdown voltages (B, ∼40 V mm-1). The pentavalent antimony or niobium acts as donor and increases the electronic conductivity. The crucial parameter for obtaining low breakdown voltage is the grain size, which depends upon sintering duration and temperature of these oxide ceramics.

  13. 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,

  14. 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.

  15. Long term characterization of voltage references

    CERN Document Server

    Halloin, Hubert; Brossard, Julien

    2013-01-01

    We report here the characterization (temperature coefficients and noise level) of selected voltage references in the frequency range from 10^(-5) to 10 Hz. The goal of this work is to update previous studies, with a characterization at lower frequencies, and find voltage references that may be suitable for the space-based interferometry mission eLISA. The requirements of relative output stability of 1 ppm/$\\sqrt{\\text{Hz}}$ down to 0.1 mHz were not met by any of the tested devices, but 4 references approaches the objective : the AD587UQ, the MAX6126AASA50, the LT1021-BCN8-5 and the LT6655BHM. While the first three were already identified as potential devices in previous studies, the later is a new promising candidate using a different technology (bandgap).

  16. Voltage stress effects on microcircuit accelerated life test failure rates

    Science.gov (United States)

    Johnson, G. M.

    1976-01-01

    The applicability of Arrhenius and Eyring reaction rate models for describing microcircuit aging characteristics as a function of junction temperature and applied voltage was evaluated. The results of a matrix of accelerated life tests with a single metal oxide semiconductor microcircuit operated at six different combinations of temperature and voltage were used to evaluate the models. A total of 450 devices from two different lots were tested at ambient temperatures between 200 C and 250 C and applied voltages between 5 Vdc and 15 Vdc. A statistical analysis of the surface related failure data resulted in bimodal failure distributions comprising two lognormal distributions; a 'freak' distribution observed early in time, and a 'main' distribution observed later in time. The Arrhenius model was shown to provide a good description of device aging as a function of temperature at a fixed voltage. The Eyring model also appeared to provide a reasonable description of main distribution device aging as a function of temperature and voltage. Circuit diagrams are shown.

  17. BRIDGING THE DIGITAL DIVIDE: WITH SPECIAL REFERENCE TO ...

    African Journals Online (AJOL)

    This paper describes the digital divide in Africa with special reference to Nigeria ... south. This digital divide also exists within the countries of the south, between the ... enterprises (SMEs) (Ugboma, 2010) Bridging the digital divide will help to ... resources are being diverted towards meeting the challenges of the pandemic in.

  18. The benefit of dividing an indirect thermal storage into two compartments: Discharge experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ragoonanan, Vishard; Davidson, Jane H.; Mantell, Susan C. [Department of Mechanical Engineering, 111 Church Street, S.E. Minneapolis, MN 55455 (United States); Homan, Kelly O. [Department of Mechanical and Aerospace Engineering, University of Missouri-Rolla, 1870 Miner Circle, Rolla, MO 65409 (United States)

    2006-01-15

    Experiments are presented to demonstrate the benefits of dividing an indirect thermal storage into two compartments. The transient discharge experiments were conducted in an undivided and equally divided 126l rectangular storage vessel, which has a height to depth aspect ratio of 9.3:1 and is inclined at 30{sup o} to the horizontal. A 240-tube copper heat exchanger with a total surface area of 2.38m{sup 2} was immersed in the storage fluid. For the divided storage, the heat exchanger flow path was in series through the two compartments. Water flow rate through the heat exchanger was varied from 0.05 to 0.15kg/s to demonstrate the effect of varying the number of transfer units (NTU) from 2.2 to 7 on the relative performance of undivided and divided storage vessels. Reported measurements include transient storage temperature distribution, heat exchanger outlet temperature, delivered energy, and exergy of the divided and undivided storage. The divided storage provides higher energy delivery rates and higher heat exchanger outlet temperatures during most of the discharge. The magnitude of these benefits depends on NTU and the extent of discharge. For a flow rate of 0.05kg/s, corresponding to a nominal NTU of 7, the divided storage delivers a maximum of 11% more energy than the undivided storage when 100l of hot water or 55% of the stored energy has been delivered. For a flow rate of 0.15kg/s, corresponding to a nominal NTU of 2.5, the divided storage delivers a maximum of 5% more energy at the same level of discharge. Data agree with first and second law analyses of a storage system comprised of two tanks in series. (author)

  19. Digital divide in education : a shift to ethical usage

    OpenAIRE

    2014-01-01

    Under the trend of ICT implementation in education, students’ learning becomes highly reliant on ICT. A student will thus suffer in his / her learning process if he / she lacks the chance of using ICT at home. This is what a divide in student’s learning is. As the occurrence of this divide is due to digital ICT devices and its effect is focussed on students’ academic performance, such divide is termed as digital divide in education (DDE). To bridge this divide, most governments around the wor...

  20. Moderately nonlinear diffuse-charge dynamics under an ac voltage

    Science.gov (United States)

    Stout, Robert F.; Khair, Aditya S.

    2015-09-01

    The response of a symmetric binary electrolyte between two parallel, blocking electrodes to a moderate amplitude ac voltage is quantified. The diffuse charge dynamics are modeled via the Poisson-Nernst-Planck equations for a dilute solution of point-like ions. The solution to these equations is expressed as a Fourier series with a voltage perturbation expansion for arbitrary Debye layer thickness and ac frequency. Here, the perturbation expansion in voltage proceeds in powers of Vo/(kBT /e ) , where Vo is the amplitude of the driving voltage and kBT /e is the thermal voltage with kB as Boltzmann's constant, T as the temperature, and e as the fundamental charge. We show that the response of the electrolyte remains essentially linear in voltage amplitude at frequencies greater than the RC frequency of Debye layer charging, D /λDL , where D is the ion diffusivity, λD is the Debye layer thickness, and L is half the cell width. In contrast, nonlinear response is predicted at frequencies below the RC frequency. We find that the ion densities exhibit symmetric deviations from the (uniform) equilibrium density at even orders of the voltage amplitude. This leads to the voltage dependence of the current in the external circuit arising from the odd orders of voltage. For instance, the first nonlinear contribution to the current is O (Vo3) which contains the expected third harmonic but also a component oscillating at the applied frequency. We use this to compute a generalized impedance for moderate voltages, the first nonlinear contribution to which is quadratic in Vo. This contribution predicts a decrease in the imaginary part of the impedance at low frequency, which is due to the increase in Debye layer capacitance with increasing Vo. In contrast, the real part of the impedance increases at low frequency, due to adsorption of neutral salt from the bulk to the Debye layer.

  1. 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.

  2. Effects of high voltage electrical stimulation on the rate of pH decline, meat quality and color stability in chilled beef carcasses

    Institute of Scientific and Technical Information of China (English)

    Ehsan Gharib Mombeni; Manoochehr Gharib Mombeini; Lucas Chaves Figueiredo; Debora Testoni Dias

    2013-01-01

    Objective:To determine the effects of high voltage electrical stimulation (HVES, 800 Voltage) on rapid decreases in pH values and improvements in meat quality. Methods:A total of 50 beef carcasses were applied, divided into two groups, one as a control and another for HVES. Meat quality was evaluated based on M. longissimus dorsi by examining pH and temperature levels at 1, 2, 5, 10 and 24 h, while color stability was examined seven days after slaughter. Results:HVES decreased the pH values of the meat and accelerated rigor mortis (P Conclusion:the HVES had positive effects on meat quality and color stability, in contrast to undesirable consumer preferences.

  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. 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.

  5. Variation-aware adaptive voltage scaling for digital CMOS circuits

    CERN Document Server

    Wirnshofer, Martin

    2013-01-01

    Increasing performance demands in integrated circuits, together with limited energy budgets, force IC designers to find new ways of saving power. One innovative way is the presented adaptive voltage scaling scheme, which tunes the supply voltage according to the present process, voltage and temperature variations as well as aging. The voltage is adapted “on the fly” by means of in-situ delay monitors to exploit unused timing margin, produced by state-of-the-art worst-case designs. This book discusses the design of the enhanced in-situ delay monitors and the implementation of the complete control-loop comprising the monitors, a control-logic and an on-chip voltage regulator. An analytical Markov-based model of the control-loop is derived to analyze its robustness and stability. Variation-Aware Adaptive Voltage Scaling for Digital CMOS Circuits provides an in-depth assessment of the proposed voltage scaling scheme when applied to an arithmetic and an image processing circuit. This book is written for engine...

  6. 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...

  7. 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.

  8. 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.

  9. 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....

  10. 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.

  11. 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.

  12. An Empirical Analysis of the Determinants of International Digital Divide

    Science.gov (United States)

    Yun, Liu

    International Digital Divide is an imbalance state of ICT penetration between countries. This paper analyzes the current status and trends of international digital divide, adopts Gompertz technology diffusion model to verify the determinants of ICT penetration level and diffusion rate separately. Finally, China should use "policy levers" to strengthen international trade cooperation, improve the capability of independent innovation, and achieve Chinese goal of bridging digital divide.

  13. A Super Performance Bandgap Voltage Reference with Adjustable Output for DC-DC Converter

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper presents a super performance bandgap voltage reference for DC-DC converter with adjustable output. It generates a wide range of voltage reference ranging from sub- 1V to 1.221 7 V and has a low temperature coefficient of 2.3 × 10 - 5/K over the temperature variation using the current feedback and resistive subdivision. In addition, the power supply rejection ration of the proposed bandgap voltage reference is 78 dB. When supply voltage varies from 2.5 V to 6 V, output VREF is 1.221 685 ± 0.055 mV.

  14. 高压输电线路巡线机器人行走电机温度检测系统的研究%High voltage transmission line inspection robot walking motor temperature detection system

    Institute of Scientific and Technical Information of China (English)

    占必红; 麦晓明; 吴功平; 王珂; 杨智勇; 彭向阳

    2015-01-01

    This paper analyzes the necessity of transmission line robot walking motor temperature real-time detection from both motor and encoder performances.A brushed DC motor heating model and a heat transfer model are proposed to calculate the temperature difference of the motor winding and the external environment successfully.It describes the measurement and control system of inspection robot motor temperature and mounting structure of the temperature sensor.Using the temperature sensor for temperature detection and the human-computer interaction platform with a ground station is used to real-time display walking motor temperature in the live running process.Temperature preset value are set in the robot control program.Compared with preset temperature limit,robot will stop the ongoing movement when the measured temperature value is higher than the upper limit value,or else the robot will continue to run.Thus,the robot can achieve intelligent control.Meanwhile,a linear regression model of temperature sensor is built based on Gaussian-Markov assumption,and based on the assumption to dopt the method of least squares method to effective correct the temperature of measurement.%从电机性能和编码器性能两方面分析了对巡线机器人行走电机温度进行实时检测的必要性.提出了一种有刷直流电机发热模型及传热模型,并通过模型成功计算出电机绕组与外界环境的温度差值.介绍了巡线机器人行走电机温度的检测控制系统及温度传感器的安装结构.采用温度传感器DS18 B20进行温度检测,用地面基站人机交互平台实时显示机器人现场运行过程中行走电机温度.在机器人控制程序中设定温度预设值,将所测得温度值与预设温度上限值进行比较,当所测得温度值高于上限值时,机器人将停止正在进行的运动,直至所测得温度低于预设值.以此实现机器人的智能控制.同时,基于高斯-马尔科夫的假设建立了温度传

  15. Resistor dividers on the march; Vorwaerts mit ohmschen Spannungsteilern

    Energy Technology Data Exchange (ETDEWEB)

    Wollschlaeger, P. [Siemens AG, Erlangen (Germany). Bereich Energieuebertragung und -verteilung

    2000-02-07

    Rising costs and the growing scope of functions demanded nowadays of a medium-voltage switchpanel are forcing manufactures to turn to innovative, intelligent solutions. Frequently, customer specifications cannot be costeffectively met with conventional technology; new ground has to be broken. A typical example is the superseding of conventional voltage transformers (with separate cores for protection and measurement) by a voltage sensor with interface to an instrument amplifier. The advantages are clear: Voltage sensors that no longer need to be configured according to network data and purpose of use. It is time for sensorics to find their way into medium voltage equipment; in industrial processes sensors are already long established. (orig.) [German] Steigender Kostendruck bei gleichzeitig zunehmender Funktionalitaet, die heute von einem Mittelspannungsschaltfeld gefordert wird, zwingt den Hersteller zu neuen, intelligenten Loesungen. Zunehmend sind die Kundenwuensche mit konventioneller Technik nicht mehr kostenguenstig zu realisieren, sondern erfordern es, neue Wege zu beschreiten. Ein Beispiel dafuer ist der Ersatz konventioneller Spannungswandler mit getrennten Kernen fuer Schutz und Messung durch einen Spannungssensor mit Schnittstelle zu einem Messverstaerker. Der Vorteil sind Spannungssensoren, die nicht mehr individuell nach Netzdaten und Verwendungszweck projektiert werden muessen. Es wird Zeit, dass die Sensortechnik auch in der Mittelspannung einzieht - in industriellen Prozessen sind Sensoren schon lange im Einsatz. (orig.)

  16. The Digital Divide and Health Outcomes: A Teleretinal Imaging Study

    Science.gov (United States)

    Connolly, Kathleen Kihmm

    2013-01-01

    The purpose of this research project was to understand, explore and describe the digital divide and the relationship between technology utilization and health outcomes. Diabetes and diabetic eye disease was used as the real-life context for understanding change and exploring the digital divide. As an investigational framework, a telemedicine…

  17. Digital Natives and Digital Divide: Analysing Perspective for Emerging Pedagogy

    Science.gov (United States)

    Onye, Uriel U.; Du, Yunfei

    2016-01-01

    This paper addresses the concepts of digital natives and digital divide from the perspective of the digital outsiders (part of digital natives). It takes a critical look at the implications of available ICT in both developed and underdeveloped countries in the fight against digital divide. The major contribution to literature is by drawing…

  18. The Digital Divide in Health Education: Myth or Reality?

    Science.gov (United States)

    Stellefson, Michael; Chaney, Beth; Chaney, Don

    2008-01-01

    Although e-health interventions provide new opportunities for health education, there has been cause for concern regarding the purported information technology gap between those who have access to digital applications and those who do not--termed the "digital divide." The literature suggests, however, that this divide may now be illusory, driven…

  19. Distance Education and the Digital Divide: An Academic Perspective

    Science.gov (United States)

    Block, Judy

    2010-01-01

    This paper will address how the digital divide affects distance education. Lack of access for some students does raise concerns. Access to technology is often defined by what students don't have: what is called a digital divide. Access also is defined by the speed of Internet connections. Access in the future will be even greater as more computers…

  20. Bridging the Digital Divide--An Australian Story

    Science.gov (United States)

    Broadbent, Robyn; Papadopoulos, Theo

    2013-01-01

    There is increasing evidence that the lack of access to information and communication technology (ICT) or the "digital divide" severely limits education, employment and economic prospects. This paper reports on the evaluation of a project that aims to bridge the digital divide. In particular, the case study data has been used to bring to…

  1. Evaluation of Fatih Project in the Frame of Digital Divide

    Science.gov (United States)

    Karabacak, Kerim

    2016-01-01

    The aim of this research realized at the general survey model is to evaluate "FATIH Project" in the frame of digital divide by determining the effects of the distributed tablets to the students being educated at K-12 schools on digital divide. Sample is taking from the 9th grade students in Sakarya city in the 2013-2014 academic session.…

  2. Rethinking the Digital Divide: Impacts on Student-Tutor Relationships

    Science.gov (United States)

    Underwood, Jean D. M.

    2007-01-01

    This article emerged from a series of debates and workshops on the impact of the Digital Divide on educational practice at the "Futures of Learning: New Learning Paradigms Conference" in Paris. The conceptualisation of the Digital Divide into the "haves" and the "have-nots", with a perception of the economically…

  3. The Digital Divide and Health Outcomes: A Teleretinal Imaging Study

    Science.gov (United States)

    Connolly, Kathleen Kihmm

    2013-01-01

    The purpose of this research project was to understand, explore and describe the digital divide and the relationship between technology utilization and health outcomes. Diabetes and diabetic eye disease was used as the real-life context for understanding change and exploring the digital divide. As an investigational framework, a telemedicine…

  4. Crossing the Phantom divide line in the Chaplygin gas model

    CERN Document Server

    Sadjadi, H Mohseni

    2009-01-01

    The role of the interaction in crossing the phantom divide line in the Chaplygin gas model is discussed. We obtain some general properties of the interactions that allow the model to arrive at the phantom divide line. We show that these properties put some conditions on the ratio of dark matter to dark energy density.

  5. 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....

  6. Solution-processed and low-temperature metal oxide n-channel thin-film transistors and low-voltage complementary circuitry on large-area flexible polyimide foil

    NARCIS (Netherlands)

    Rockelé, M.; Pham, D.V.; Steiger, J.; Botnaras, S.; Weber, D.; Vanfleteren, J.; Sterken, T.; Cuypers, D.; Steudel, S.; Myny, K.; Schols, S.; Putten, J.B.P.H. van der; Genoe, J.; Heremans, P.

    2012-01-01

    High-performance solution-based n-type metal oxide thin-film transistors (TFTs), fabricated directly on polyimide foil at a post-annealing temperature of only 250''C, are realized and reported. Saturation mobilities exceeding 2cmV(Vs) and on-to-off current ratios up to 10^ are achieved. The usage of

  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. Precision monitoring and calibration of the high-voltage for the KATRIN experiment; Praezisionsueberwachung und Kalibration der Hochspannung fuer das KATRIN-Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Thuemmler, T.

    2007-11-12

    The goal of the KATRIN(KArlsruhe TRIritium Neutrino) Experiment is to directly determine the neutrino rest mass from the kinematics of the tritium-{beta}-decay. KATRIN uses the high resolution and luminosity of a spectrometer following the MAC-E filter principle. Based on the experience of the successful predecessor experiments in Mainz and Troisk and the improved experimental technology, KATRIN aims to reach a sensitivity on the neutrino mass of 0.2 eV/c{sup 2} (90% C.L.). One of the few systematic uncertainties that have to be reduced to meet this goal is the uncertainty of measuring and monitoring the potential of the electrostatic filter of the spectrometer. In tritium measurement mode voltages of about U{sub 0} =-18.6 kV have to be permanently monitored with a maximum uncertainty of 3.3 ppm ({approx} 61mV at U{sub 0}), in order not to add more than {delta}m{sup 2}{sub {nu}{sub ec}}{sup 4} {<=} 0.0075 eV{sup 2} to the total systematic uncertainty. The goal of this work is to build a new precision high voltage divider in cooperation with PTB Braunschweig that reaches an uncertainty of about 1 ppm at voltages up to 35 kV. The divider is based on a new type of precision resistors, which have been screened with respect to their warm up drift and their temperature coefficient at the ppm level. By combining 100 of the best matching samples, the mutual warm up effect could be reduced to a computed value of <0.02 ppm. The precision resistors are mounted in a shielded and temperature stabilized vessel under N{sub 2} gas. The properties of both installed low voltage outputs with the ratios 1972:1 and 3944:1 have been repeatedly calibrated with about one year time difference at the DC high voltage laboratory (division 2.31) of PTB. The performance of the new divider in real measurements has been tested with the prototype of the new condensed {sup 83m}Kr calibration source (CKrS) [Ost08] at the Mainz spectrometer. Detailed stability investigations of the energy of the {sup

  9. 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.

  10. 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 ...

  11. 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.

  12. 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,...

  13. 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.

  14. 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.

  15. Built-in voltage of a silicon p-n junction having a heavily doped region

    Science.gov (United States)

    Sinha, Amitabha

    1984-01-01

    An analysis of the built-in voltage of a silicon p-n junction has been done, taking into account the band-gap narrowing effects in the heavily doped region. It has been observed that much lower values of built-in voltage are obtained when heavy doping effects are considered. Also, the magnitude of built-in voltage decreases when the temperature of the p-n junction is increased.

  16. Surge current capabilities and isothermal current-voltage characteristics of high-voltage 4H-SiC junction barrier Schottky rectifiers

    Science.gov (United States)

    Palmour, J. W.; Levinshtein, M. E.; Ivanov, P. A.; Zhang, Q. J.

    2015-06-01

    Isothermal forward current-voltage characteristics of high-voltage 4H-SiC junction barrier Schottky rectifiers (JBS) have been studied for the first time. Isothermal characteristics were measured with JBS having a blocking voltage of 1700 V up to a current density j  ≈  4200 A cm-2 in the temperature range 297-460 K. Quasi-isothermal current-voltage characteristics of these devices were studied with injection of minority carriers (holes) up to j  ≈  7200 A cm-2 and ambient temperatures of 297 and 460 K. The isothermal forward current-voltage characteristics make it possible to numerically calculate (for example, by an iteration procedure) the overheating in an arbitrary operation mode.

  17. 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.

  18. 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.

  19. 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.

  20. Over Voltage in a Multi-sectioned Solenoid during a Quenching

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xinglong; Wang, Li; Pan, Heng; Wu, Hong; Liu, Xiaokun; Chen, Anbin; Green, M.A.; Xu, F.Y.

    2009-06-21

    Accurate analysis of over voltage in the superconducting solenoid during a quench is one of the bases for quench protection system design. Classical quench simulation methods can only give rough estimation of the over voltage within a magnet coil. In this paper, for multi-sectioned superconducting solenoid, based on the classical assumption of ellipsoidal normal zone, three-dimension al temperature results are mapped to the one-dimension of the wire, the temperature distribution along the wire and the resistances of each turn are obtained. The coil is treated as circuit comprised of turn resistances, turn self and mutual inductances. The turn resistive voltage, turn inductive voltage, and turn resultant voltage along the wire are calculated. As a result, maximum internal voltages, the layer-to-layer voltages and the turn-to-turn voltages are better estimated. Utilizing this method, the over voltage of a small solenoid and a large solenoid during quenching have been studied. The result shows that this method can well improve the over voltage estimate, especially when the coil is larger.

  1. 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.

  2. 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

  3. Quantitative analysis of irreversibilities causes voltage drop in fuel cell (simulation and modeling)

    Energy Technology Data Exchange (ETDEWEB)

    Ghadamian, Hossein [Azad Univ., Dept. of Energy Engineering, Tehran (Iran); Saboohi, Yadolah [Sharif Energy Research Inst. (SERI), Tehran (Iran)

    2004-11-30

    Power level of a fuel cell depends on its operating condition, which is product of voltage and current-density the highest level of voltage is identified as reversible open circuit voltage (ROCV), which represents an ideal theoretical case [J. Larmin, A. Dicks, Fuel Cell System Explained, Wiley, 2000 (ISBN)]. Compared to that is ideal operating voltage which is usually characterized as open circuit voltage (OCV). An evaluation of deviation of operating voltage level from ideal operational case may provide information on the extent of improving efficiency and energy efficiency of a fuel cell. Therefore, quantification of operation deviation from OCV is the main point that is discussed in the present paper. The analysis procedure of voltage drop is based on step-by-step review of voltage drops over activation, internal currents (fuel-cross-over), Ohmic and mass-transport or concentration losses. Accumulated total voltage drops would be estimated as a sum of aforementioned losses. The accumulated voltage drops will then be reduced from OCV to obtain the operating voltage level. The above numerical analysis has been applied to identify the extents of voltage drop. The possible reducing variables in voltage drops reviewed and concluded that the activation loss has considerable impact on total voltage drops and it explains the most part of total losses. It is also found that the following correspondence parameters cause decrease in voltage drops: 1. Temperature increasing; 2. Pressure increasing; 3. Hydrogen or oxygen concentration increasing; 4. Electrode effective surface increasing; 5. Electrode and electrolyte, conductivity modification; 6. Electrolyte thickness reducing up to possible limitation; 7. Connection modification. (Author)

  4. A Novel Chopper Circuit Having Divided Multi-load

    Science.gov (United States)

    Yamamoto, Isamu; Matsui, Keiju; Mori, Hideki; Yao, Yugo

    A dc-dc converter is being widely used for various household appliances and for industry applications. The dc-dc converter is powered from single battery, and the voltage is varied according to the purpose. In the vehicle, various accessories whose electric power is different are being used. Thus, plural number of dc-dc converter should be provided, so these situations bring complicated circuits, and accordingly, higher cost. Moreover, this is not limited to the vehicle applications. For instance, for analog circuits and digital circuits, various power supplies with different voltages are used sometimes. Under such backgrounds, in this paper, we propose a novel dc-dc converter with simply circuit configuration which can supply to two or more different output loads. This converter can control output voltages by controlling duty ratio by using typically two switching devices, which is composed by single boost-switch and single buck-switch. The output voltage can be controlled widely. A few modified circuits developed from the fundamental circuit are represented including the general multi-load circuit. Theoretical equations are solved, where results are confirmed by simulations and experiments.

  5. 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.

  6. 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

  7. 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.

  8. A Line Dividing "Trademark License" and "Trademark Infringement"

    Institute of Scientific and Technical Information of China (English)

    Chi Shaojie

    2004-01-01

    @@ Opinions are not divided on in fringement by another person's use of a registered trademark without license from the trademark registrant,nor on the non-infringement by its/his licensed use of a registered trademark.

  9. Continental Divide of the United States - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map layer portrays the Continental Divide of the United States. The map layer was created by extracting Hydrologic Unit Boundary line features from an existing...

  10. Annan warns of 'content divide' between rich and poor

    CERN Multimedia

    Dickson, D

    2003-01-01

    "The Secretary-General of the United Nations, Kofi Annan, warned today (10 December) that a "content divide" is threatening to deprive developing countries of the full benefits offered by information and communications technologies (ICTs)" (1 page)

  11. Elevated temperature performance of high voltage Li1+yMn1.5Ni0.5O4-xFx spinel in window-shifted Li-ion cells

    Science.gov (United States)

    Pereira, Nathalie; Ruotolo, Michael C.; Lu, Matthew Y.; Badway, Fadwa; Amatucci, Glenn G.

    2017-01-01

    Although the LiMn1.5Ni0.5O4 spinel operating at 4.7 V presents some beneficial characteristics over more traditional positive electrode materials, instability issues at elevated temperature have limited its practical use so far. While we previously proposed Li1+yMn1.5Ni0.5O4-xFx (LMNOF) spinel that is intrinsically stable at elevated temperatures in Li-excess half-cell configuration, we investigate herein fixed, non-excess Li-content window-shifted Li-ion systems. By utilizing Li4Ti5O12 (LTO) or TiS2 negative electrodes stable in broad electrolyte compositions instead of carbonaceous electrodes, we aim at limiting the Li-consuming side reactions such as the formation of solid-electrolyte interphase and enable a focus on the exploration of electrolyte compositions including additives. Utilizing such an approach, excellent fundamental stability of LMNOF in a fixed Li-content Li-ion environment is demonstrated at 55 °C with the use of relatively common electrolyte components.

  12. An improved fractional divider for fractional-N frequency synthesizers

    Science.gov (United States)

    Zhang, Wei; Liu, Yang; Zhou, Yongqi

    2009-07-01

    This paper presents an improved fractional divider used in 1.8~2GHz fractional-N frequency synthesizers. A new clock setting for delta-sigma modulator (DSM) is proposed to prevent the potential problems of traditional fractional dividers: the DSM output would be wrongly loaded and the action of DSM circuit may affect the phase-detection of phase-frequency-detector (PFD). Simulation result shows the effectiveness of this improvement.

  13. Agile Development & Software Architecture - Crossing the Great Divide

    Science.gov (United States)

    2016-06-07

    2010 Carnegie Mellon University SEI Webinar Series: Agile Development & Software Architecture – Crossing the Great Divide Software Engineering...2010 4. TITLE AND SUBTITLE Agile Development & Software Architecture - Crossing the Great Divide 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...Mellon University , Software Engineering Institute,Pittsburgh,PA,15213 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S

  14. 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

  15. Effect of temperature on the electronic/ionic transport properties of porous LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} with high voltage for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Yongli, E-mail: lilyshuoxu@163.com; Wang, Mingzhen; Wang, Jiali; Zhuang, Quanchao, E-mail: zhuangquanchao@126.com

    2016-09-01

    Porous spinel LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} microspheres were successfully synthesized by a facile method with microspheres MnCO{sub 3} template, and characterized by XRD and SEM. The as-synthesized porous LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} microspheres exhibit high rate capability and good cycle performance, with the specific discharge capacity of 125.5, 125.4, 121 and 97.6 mA h/g at 1, 2, 3 and 5 C, respectively, and the capacity retention of 85.6% at 5 C after 100 cycles, which are attributed to the porous structure. It is found that the EIS features of spinel LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} cathode are related to the temperature, and the middle to high frequency arc is observed in the Nyquist diagram at temperatures below zero, which is attributed to the electronic properties of the electrode material. In 1 mol/L LiPF{sub 6}-EC:DEC:DMC electrolyte solutions, the energy barriers for the ion jump related to migration of lithium ions through the SEI film of the spinel LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} cathode are determined to be 16.89 kJ/mol, the thermal activation energy of the electronic conductivity to be 0.348 eV, and the intercalation-deintercalation reaction activation energies to be 0.619 eV, respectively. - Highlights: • Porous spinel LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} microspheres cathode were synthesized. • Porous LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} microspheres show high rate and excellent cycle characteristic. • The EIS features of spinel LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} have related to temperature. • Three different energies of kinetic characterization at 4.7 V are calculated.

  16. 大型高压干式潜水电机定子三维温度场有限元分析%Calculation of Stator 3D Temperature Field for Large-size High-voltage Dry Submersible Motor

    Institute of Scientific and Technical Information of China (English)

    鲍晓华; 吕强; 王瑞男; 朱庆龙; 刘冰

    2011-01-01

    本文根据传热学理论,建立了大型潜水电机定子三维温度场的数学模型,给出了潜水电机导热系数及散热系数的计算方法.应用有限元法对潜水电机定子三维温度场进行分析计算,并将结果与实际测量值进行比较,验证了所述方法的正确性和实用性.最后,对潜水电机采用不同绝缘等级时电机定子温度场进行了数字模拟研究,得出了一些十分有益的结论,对潜水电机设计及其优化工作具有重要的指导意义.%The 3D mathematical model of the stator temperature field over the large submersible motor are developed based on heat transfer theory. The method of calculating the conductivity and thermal coefficient about submersible motor is given. The finite element method is used to calculate the 3D stator thermal field about submersible motor, and the rationality of the thermal field calculation method and the validity of the calculated values are verified by experimental results. The influence of different insulation in the motor stator temperature field are analysed, which could help optimum design of submersible motor in future applications.

  17. Fast and accurate method for computing ATC with voltage stability

    CERN Document Server

    Eidiani, M; Vahedi, E

    2002-01-01

    Order 889 mandated each control area to computer ATC (Available Transfer Capability) and post them on a communication system called the Open Access Same-time Information System (OASIS). Approaches of computing ATC can be divided into the following groups: Static and Dynamic methods. This paper presents a fast method for ATC calculations with voltage stability termination criteria. We use estimation of the determinant of Jacobian matrix for assessment of voltage stability. This method is compared with these methods: different between energy in SEP (Stable Equilibrium Point) and UEP (Unstable Equilibrium Point), ts index of Dr.Chiang and continuation power flow. The idea are demonstrated on 2, 3, 7 (CIGRE), 10, 30 (IEEE) and 145 bus (Iowa State University).

  18. Structural transformation of Ge dimers on Ge(001) surfaces induced by bias voltage

    Institute of Scientific and Technical Information of China (English)

    Qin Zhi-Hui; Shi Dong-Xia; Gao Hong-Jun

    2008-01-01

    Scanning tunnelling microscopy is utilized to investigate the local bias voltage tunnelling dependent transformation between (2×1) and c(4×2) structures on Ge(001) surfaces, which is reversibly observed at room temperature and a critical bias voltage of -0.80 V. Similar transformation is also found on an epitaxial Ge islands but at a slightly different critical bias voltage of -1.00V. It is found that the interaction between the topmost atoms on the STM tip and the atoms of the dimers, and the pinning effect induced by Sb atoms, the vacancies or the epitaxial clusters, can drive the structural transformation at the critical bias voltage.

  19. Neural Correlates of Divided Attention in Natural Scenes.

    Science.gov (United States)

    Fagioli, Sabrina; Macaluso, Emiliano

    2016-09-01

    Individuals are able to split attention between separate locations, but divided spatial attention incurs the additional requirement of monitoring multiple streams of information. Here, we investigated divided attention using photos of natural scenes, where the rapid categorization of familiar objects and prior knowledge about the likely positions of objects in the real world might affect the interplay between these spatial and nonspatial factors. Sixteen participants underwent fMRI during an object detection task. They were presented with scenes containing either a person or a car, located on the left or right side of the photo. Participants monitored either one or both object categories, in one or both visual hemifields. First, we investigated the interplay between spatial and nonspatial attention by comparing conditions of divided attention between categories and/or locations. We then assessed the contribution of top-down processes versus stimulus-driven signals by separately testing the effects of divided attention in target and nontarget trials. The results revealed activation of a bilateral frontoparietal network when dividing attention between the two object categories versus attending to a single category but no main effect of dividing attention between spatial locations. Within this network, the left dorsal premotor cortex and the left intraparietal sulcus were found to combine task- and stimulus-related signals. These regions showed maximal activation when participants monitored two categories at spatially separate locations and the scene included a nontarget object. We conclude that the dorsal frontoparietal cortex integrates top-down and bottom-up signals in the presence of distractors during divided attention in real-world scenes.

  20. Generation of five phase-locked harmonics by implementing a divide-by-three optical frequency divider

    CERN Document Server

    Suhaimi, Nurul Sheeda; Gavara, Trivikramarao; Nakagawa, Ken'ichi; Hong, Feng Lei; Katsuragawa, Masayuki

    2015-01-01

    We report the generation of five phase-locked harmonics, f_1: 2403 nm, f_2: 1201 nm, f_3: 801 nm, f_4: 600 nm, and f_5: 480 nm with an exact frequency ratio of 1 : 2 : 3 : 4 : 5 by implementing a divide-by-three optical-frequency divider in the high harmonic generation process. All five harmonics are generated coaxially with high phase coherence in time and space, which are applicable for various practical uses.

  1. [Promoting nursing competitiveness: introduction to the digital divide].

    Science.gov (United States)

    Lin, Chun-Hsu; Lee, Ting-Ting

    2010-02-01

    Increasingly sophisticated information technology (IT) has widened the gap (the so-called "digital divide") between those with effective access to IT resources and those without. Problems related to the digital divide exist in every country. In addition to level of familiarity with technology, the divide can also be influenced by factors of race, gender, age, education, economic status and area of residence. The digital divide may be ameliorated through technology innovations in terms of access to information, information application and information literacy. As IT is an increasingly significant component of modern healthcare, it may be expected that the "width" of the potential gap widens as IT applications increase in sophistication. Nursing professionals must keep abreast of advancing technologies in order to narrow the digital divide. To cope with this challenge, nursing professionals should enhance their understanding of new technologies beyond what is taught in formal education curricula. This knowledge enhancement may be attained through self learning or on-the-job training in nursing informatics. Content could cover hospital information system (IS) usage, security, applications and web access. This will improve the ability of nursing staff to face the current IT challenge.

  2. Romania's Digital Divide and the Failures of E-Government

    Directory of Open Access Journals (Sweden)

    Sorin Dan ŞANDOR

    2006-02-01

    Full Text Available This paper tries to measure the level of the digital divide existing in Romania and also to verify its relationship with e-government. At the country level, Romania is one of the least digitally developed countries in Europe, but it has shown a sharp increase in recent years. At the social level, based on data from public opinion surveys, digital divide is analyzed at two levels: lack of access and lack of knowledge. The results are similar to those in other countries: digital divide appears along the same dimensions: rural/urban, age, education, wealth and, to a lesser extent, gender. E-government services, while presumed to be at an adequate level, are used only by a very small number of citizens, thus having no impact upon the digital divide. Confronted with a serious divide, and with great possibility of its increasing, Romania needs to promote policies designed to increase access and knowledge. Also, e-government is not possible, unless administrative culture and procedures change.

  3. High Voltage Power Transmission for Wind Energy

    Science.gov (United States)

    Kim, Young il

    The high wind speeds and wide available area at sea have recently increased the interests on offshore wind farms in the U.S.A. As offshore wind farms become larger and are placed further from the shore, the power transmission to the onshore grid becomes a key feature. Power transmission of the offshore wind farm, in which good wind conditions and a larger installation area than an onshore site are available, requires the use of submarine cable systems. Therefore, an underground power cable system requires unique design and installation challenges not found in the overhead power cable environment. This paper presents analysis about the benefit and drawbacks of three different transmission solutions: HVAC, LCC/VSC HVDC in the grid connecting offshore wind farms and also analyzed the electrical characteristics of underground cables. In particular, loss of HV (High Voltage) subsea power of the transmission cables was evaluated by the Brakelmann's theory, taking into account the distributions of current and temperature.

  4. Effects of High-Voltage Electrical Stimulation in Improving the Viability of Musculocutaneous Flaps in Rats.

    Science.gov (United States)

    Neves, Lais Mara Siqueira das; Guirro, Elaine Caldeira de Oliveira; Albuquerque, Fernanda Luiza de Almeida; Marcolino, Alexandre Marcio

    2016-10-01

    The musculocutaneous flap of the transverse rectus abdominis muscle is a technique used for breast reconstruction, and one of the complications of this procedure is tissue necrosis. The objective of the study is to determine the effect of high-voltage electrical stimulation (HVES) in the transverse rectus abdominis muscle flap in rats. Fourteen rats underwent surgery for obtaining the flap. The rats were distributed into 2 homogeneous groups: group 1 underwent both surgery and the use of HVES, whereas group 2 underwent just the surgery (control). Electrical stimulation was applied immediately after surgery and for 2 consecutive days. The percentage of necrotic area was analyzed using the Image J software, and blood flow was assessed by infrared thermography in different regions of the flap, divided into 4 zones according to the proximity of the pedicle of the inferior epigastric artery. The results were analyzed using a Student t test, where group 1 experienced a necrotic area of 26.2%, and group 2 had an area of 54.5%. Regarding the temperature, the 2 groups showed increase in the minimum and maximum temperature on the fourth postoperative day. The HVES appeared to have a positive influence on the viability of the flap.

  5. 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.

  6. 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

  7. 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.

  8. Adjustable low-voltage bandgap reference on chip%在芯片可调低电压带隙基准源设计

    Institute of Scientific and Technical Information of China (English)

    孙峥; 石会; 马光彦; 徐勇; 黄颖

    2014-01-01

    With the development of CMOS process and wide application of low-voltage bandgap reference, the low-voltage bandgap reference design based on CMOS process has great practical significance.An ad-j ustable low-voltage bandgap reference based on bandgap core was presented in this paper,and an adj usta-ble output voltage with zero temperature coefficient at room temperature needed by the high speed dual-modulus divider could be realized by paralleling minimum number of resistors next to the bipolar tran-sistor.In addition,some influencing factors such as feedback loop,offset voltage and open-loop gain of OPA were discussed,and correlative analysis formulas given.The circuit is fabricated in 0.18μm standard CMOS process and simulation results show that the power supply rejection ratio (PSRR)is -48 dB,and that the temperature coefficient is 8.3×10-6/℃ in the temperature range from-40 ℃ to+125 ℃.Above data demonstrate that the circuit gains good comprehensive performance including low- temperature drift,high- precision and so on which can meet the demands of system design completely.%为高速双模预分频器提供所需的稳定的参考电平,提出了一种基于带隙基准核的在芯片可调低电压带隙基准源电路设计方法,通过在双极型晶体管的附近并联少量电阻,获得数值可调的、常温下具有零温度系数的低电压基准。讨论了运放的反馈环路、失调电压以及开环增益等各项因素对基准电压精度的影响,并给出了相关的分析公式。设计采用0.18μm 数模混合 CMOS 工艺。仿真结果表明,电路的电源抑制比(PSRR)为-48 dB,-40℃~+125℃温度变化范围内的温漂系数为8.3×10-6/℃。电路综合性能良好,能满足低温漂、高精度的设计要求。

  9. A parameter-free method to extract the superconductor’s J c(B,θ) field-dependence from in-field current-voltage characteristics of high temperature superconductor tapes

    Science.gov (United States)

    Zermeño, Víctor M. R.; Habelok, Krzysztof; Stępień, Mariusz; Grilli, Francesco

    2017-03-01

    The estimation of the critical current (I c) and AC losses of high-temperature superconductor devices through modeling and simulation requires the knowledge of the critical current density (J c) of the superconducting material. This J c is in general not constant and depends both on the magnitude (B loc) and the direction (θ, relative to the tape) of the local magnetic flux density. In principle, J c(B loc,θ) can be obtained from the experimentally measured critical current I c(B a,θ), where B a is the magnitude of the applied magnetic field. However, for applications where the superconducting materials experience a local field that is close to the self-field of an isolated conductor, obtaining J c(B loc,θ) from I c(B a,θ) is not a trivial task. It is necessary to solve an inverse problem to correct for the contribution derived from the self-field. The methods presented in the literature comprise a series of approaches dealing with different degrees of mathematical regularization to fit the parameters of preconceived nonlinear formulas by means of brute force or optimization methods. In this contribution, we present a parameter-free method that provides excellent reproduction of experimental data and requires no human interaction or preconception of the J c dependence with respect to the magnetic field. In particular, it allows going from the experimental data to a ready-to-run J c(B loc,θ) model in a few minutes.

  10. Stator insulation systems for medium voltage PWM drives fed motors

    Energy Technology Data Exchange (ETDEWEB)

    Gao, G.; Chen, W. [TECO-Westinghouse Motor Co., Round Rock, TX (United States)

    2005-07-01

    Adjustable speed drives (ASD) are commonly used in power electronics and control systems. It is estimated that more than 15 per cent of medium voltage motors are currently fed by such drives worldwide. A research project was conducted to examine the influence of medium voltage pulse width modulated (PWM) ASD on motor stator insulation systems. The findings, based on accelerated laboratory tests, have helped designers to improve the capabilities of the insulation system used for ASD-fed motors. Repetitive, high magnitude voltage spikes with fast rise time create significant stress on insulation systems. Gradual deterioration and premature failure of the motor insulation can result from surge voltages which generate surface discharges between phase windings/end windings, or partial discharges between stator turns. However, there is no industrial standard to evaluate motor insulation life under ASD-cable-motor conditions. Several material manufacturers have developed their own version of corona resistant material. However, the insulation life of ASD-fed motors does not depend solely on the raw materials. Rather, it depends on the complete insulation system, including the stator manufacturing process. In order to address this problem, TECO-Westinghouse Motor Company has developed special design criteria and manufacturing practices in order to reduce winding insulation temperature and to compensate for the additional heat generated by high frequency contents in the PWM voltage waveform. A patent pending new cooling system should reduce winding temperature by 15 to 20 degrees C. This paper presented design considerations for turn insulation, groundwall insulation, and a voltage stress grading system. A new thermal class H insulation system was also described. 6 refs., 2 tabs., 5 figs.

  11. 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)

  12. Transition State Theory for dissipative systems without a dividing surface

    CERN Document Server

    Revuelta, F; Benito, R M; Borondo, F

    2015-01-01

    Transition State Theory is a central cornerstone in reaction dynamics. Its key step is the identification of a dividing surface that is crossed only once by all reactive trajectories. This assumption is often badly violated, especially when the reactive system is coupled to an environment. The calculations made in this way then overestimate the reaction rate and the results depend critically on the choice of the dividing surface. In this Letter, we study the phase space of a stochastically driven system close to an energetic barrier in order to identify the geometric structure unambiguously determining the reactive trajectories, which is then incorporated in a simple rate formula for reactions in condensed phase that is both independent of the dividing surface and exact.

  13. Bridging the Digital Divide for urban seniors: community partnership.

    Science.gov (United States)

    Cresci, M Kay; Jarosz, Patricia A

    2010-01-01

    Computers and the Internet offer older adults resources for improving health. For many older adults, the "Digital Divide" (the social, economic, and demographic factors that exist between individuals who use computers and those who do not) is a barrier to taking advantage of these resources. Bridging the Digital Divide by making computers and the Internet more accessible and making online health information more usable for older adults has the potential to improve health of older adults. This article describes a strategy for closing the Digital Divide for urban seniors through the formation of a community- university partnership with the goal of improving health and well-being through the use of online health information.

  14. Ouroboros: A Tool for Building Generic, Hybrid, Divide& Conquer Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J R; Foster, I

    2003-05-01

    A hybrid divide and conquer algorithm is one that switches from a divide and conquer to an iterative strategy at a specified problem size. Such algorithms can provide significant performance improvements relative to alternatives that use a single strategy. However, the identification of the optimal problem size at which to switch for a particular algorithm and platform can be challenging. We describe an automated approach to this problem that first conducts experiments to explore the performance space on a particular platform and then uses the resulting performance data to construct an optimal hybrid algorithm on that platform. We implement this technique in a tool, ''Ouroboros'', that automatically constructs a high-performance hybrid algorithm from a set of registered algorithms. We present results obtained with this tool for several classical divide and conquer algorithms, including matrix multiply and sorting, and report speedups of up to six times achieved over non-hybrid algorithms.

  15. Selectively Distracted: Divided Attention and Memory for Important Information.

    Science.gov (United States)

    Middlebrooks, Catherine D; Kerr, Tyson; Castel, Alan D

    2017-08-01

    Distractions and multitasking are generally detrimental to learning and memory. Nevertheless, people often study while listening to music, sitting in noisy coffee shops, or intermittently checking their e-mail. The current experiments examined how distractions and divided attention influence one's ability to selectively remember valuable information. Participants studied lists of words that ranged in value from 1 to 10 points while completing a digit-detection task, while listening to music, or without distractions. Though participants recalled fewer words following digit detection than in the other conditions, there were no significant differences between conditions in terms of selectively remembering the most valuable words. Similar results were obtained across a variety of divided-attention tasks that stressed attention and working memory to different degrees, which suggests that people may compensate for divided-attention costs by selectively attending to the most valuable items and that factors that worsen memory do not necessarily impair the ability to selectively remember important information.

  16. Engineering the Divide-and-Conquer Closest Pair Algorithm

    Institute of Scientific and Technical Information of China (English)

    Ming-hui Jiang; Joel gillespie

    2007-01-01

    We improve the famous divide-and-conquer algorithm by Bentley and Shamos for the planar closest-pair problem. For n points on the plane, our algorithm keeps the optimal O(n log n) time complexity and, using a circle-packing property, computes at most 7n/2 Euclidean distances, which improves Ge et al.'s bound of (3n log n)/2 Euclidean distances. We present experimental results of our comparative studies on four different versions of the divide-and-conquer closest pair algorithm and propose two effective heuristics.

  17. Google and the digital divide the bias of online knowledge

    CERN Document Server

    Segev, Elad

    2010-01-01

    Beneficial to scholars and students in the fields of media and communication, politics and technology, this book outlines the significant role of search engines in general and Google in particular in widening the digital divide between individuals, organisations and states. It uses innovative methods and research approaches to assess and illustrate the digital divide by comparing the popular search queries in Google and Yahoo in different countries as well as analysing the various biases in Google News and Google Earth. The different studies developed and presented in this book provide various

  18. 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...

  19. 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...

  20. Development of a new lower hybrid antenna module using a poloidal power divider

    Energy Technology Data Exchange (ETDEWEB)

    Maebara, Sunao; Seki, Masami; Suganuma, Kazuaki [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

    1996-07-01

    The antenna using poloidal power divider is an effective method for simplification of Lower Hybrid Current Drive (LHCD) antenna system. This method should allow to reduce the power density in the antenna while maintaining a good flexibility of N{sub parallel} spectrum of waves. For this purpose, three types of poloidal power divider which split the power in three, and the 3 x 6 multi-junction module were developed. r.f. properties and outgassing of these components were evaluated using the CEA Cadarache RF Test Facility. A good power dividing ratio of 33 {+-} 4% was obtained for each of these poloidal dividers, and the reflection coefficient was lower value than 1.5%. For the 3 x 6 multi-junction, reflection coefficient was less than 1.3% and r.f. losses lower than 1.0% were measured. On the other hand, it was found in the scattering matrix analysis that reflection coefficient at plasma has to be less than a few % in order to operate these components under available conditions. In combination with two poloidal power dividers connected to the 3 x 6 multi-junction module, quasi stationary operation for r.f. injection time of 1000 sec at 300 kW was demonstrated under water cooling. In this case, it was found that the outgassing rate is in the lower range of 10{sup -7}Pam{sup 3}s{sup -1}m{sup -2} within the maximum module temperature of {approx}100degC. This report describes the experimental and analytical results of a new lower hybrid (LH) antenna module using the poloidal power divider. (author)

  1. A School Divided: One Elementary School's Response to Education Policy

    Science.gov (United States)

    Zoch, Melody

    2017-01-01

    This article examines how one elementary school was divided into two schools--a primary and an intermediate school--because of how policies were interpreted and enacted with regard to high-stakes testing. The grades in which students took high-stakes tests were privileged in terms of receiving monetary resources and support from staff. An emphasis…

  2. Nigeria united in grief; divided in response: Religious terrorism ...

    African Journals Online (AJOL)

    Nigeria united in grief; divided in response: Religious terrorism, Boko Haram, and the dynamics of state response. ... Boko Haram's avowed aim is to wrest control from the Nigerian government and to impose a strict form of Sharia law across a ...

  3. The Digital Divide and Rural Community Colleges: Problems and Prospects.

    Science.gov (United States)

    Katsinas, Stephen G.; Moeck, Pat

    2002-01-01

    Discusses the seriousness of the digital divide-the discrepancy between technology-literate and -illiterate people-in rural areas in the United States. Reports that rural young, minority, and single-parent households lag behind the national average in both personal computer ownership and Internet access. Offers suggestions for ways rural community…

  4. Fiber-optic Michelson interferometer using an optical power divider.

    Science.gov (United States)

    Imai, M; Ohashi, T; Ohtsuka, Y

    1980-10-01

    A fiber-optic interferometer consisting of a multimode fiber-optical power divider was constructed in the Michelson arrangement and applied to measure a micrometer-order displacement of the vibrating object based on an optical homodyne technique. Improvement in the sensitivity of the apparatus is discussed from the viewpoint of increasing the minimum detectable beat signal.

  5. Response Styles and the Rural-Urban Divide

    Science.gov (United States)

    Thomas, Troy D.; Abts, Koen; Vander Weyden, Patrick

    2014-01-01

    This article investigates the effect of the rural-urban divide on mean response styles (RSs) and their relationships with the sociodemographic characteristics of the respondents. It uses the Representative Indicator Response Style Means and Covariance Structure (RIRSMACS) method and data from Guyana--a developing country in the Caribbean. The…

  6. Leadership Analysis in K-12 Case Study: "Divided Loyalties"

    Science.gov (United States)

    Alsubaie, Merfat Ayesh

    2016-01-01

    This report mainly aims to provide a critical and in-depth analysis of the K-12 Case, "Divided Loyalty" by Holy and Tartar (2004). The case recounts how the manifestation of inadequate leadership skills in a school setting could affect negatively the performance of students.

  7. Dividing Attention Lowers Children's but Increases Adults' False Memories

    Science.gov (United States)

    Otgaar, Henry; Peters, Maarten; Howe, Mark L.

    2012-01-01

    The present study examined the impact of divided attention on children's and adults' neutral and negative true and false memories in a standard Deese/Roediger-McDermott paradigm. Children (7- and 11-year-olds; n = 126) and adults (n = 52) received 5 neutral and 5 negative Deese/Roediger-McDermott word lists; half of each group also received a…

  8. From Fundamentalists to Structuralists: Bridging the Digital Divide

    Science.gov (United States)

    Kok, Ayse

    2010-01-01

    The purpose of this literature review is to provide information about several ICT initiatives undertaken in education on a global basis in order to overcome the digital divide and summarise the findings of these initiatives. Due to the limited scope of the study, the bulk of the review mainly concerns initiatives undertaken in secondary schools,…

  9. The Digital Divide and Its Impact on Academic Performance

    Science.gov (United States)

    Sun, Jerry Chih-Yuan; Metros, Susan E.

    2011-01-01

    The purpose of this article is to explore issues of the digital divide and its impact on academic performance. Research shows that proper use of technology by students increases their academic performance outcomes. In the literature review section, the authors review articles and theories based on Bennett's (2001) societal equity framework. The…

  10. Journalism Students, Web 2.0 and the Digital Divide

    Science.gov (United States)

    Green, Mary Elizabeth

    2009-01-01

    The purpose of this study was to find out if students were utilizing Web 2.0 applications. Since the applications in question are often employed by the media industry, the study aspired to find out if students majoring in mass communication and journalism utilized the applications more often than other students. The "digital divide" is a term used…

  11. The Digital Divide: The Special Case of Gender

    Science.gov (United States)

    Cooper, J.

    2006-01-01

    This paper examines the evidence for the digital divide based on gender. An overview of research published in the last 20 years draws to the conclusion that females are at a disadvantage relative to men when learning about computers or learning other material with the aid of computer-assisted software. The evidence shows that the digital divide…

  12. Peculiarities of the Digital Divide in Sub-Saharan Africa

    Science.gov (United States)

    Mutula, Stephen M.

    2005-01-01

    Purpose: Seeks to argue that the peculiarities of sub-Saharan Africa, in terms of its socio-cultural diversity, low economic development, linguistic factors, HIV/AIDS pandemic, gender discrimination, low ICT awareness and so on, demand a new model of addressing the digital divide. Design/methodology/approach: Paper largely based on literature…

  13. Digital Divide among Youth: Socio-Cultural Factors and Implications

    Science.gov (United States)

    Parycek, Peter; Sachs, Michael; Schossbock, Judith

    2011-01-01

    Purpose: This paper aims to examine socio-cultural differences in internet use (Digital Divide) among 14-year-old Austrian pupils, in particular usage scenarios and research competences. It is based on a paper presented at the International Association for the Development of the Information Society e-Society conference, 10-13 March 2011, Spain…

  14. Effects of valence and divided attention on cognitive reappraisal processes.

    Science.gov (United States)

    Morris, John A; Leclerc, Christina M; Kensinger, Elizabeth A

    2014-12-01

    Numerous studies have investigated the neural substrates supporting cognitive reappraisal, identifying the importance of cognitive control processes implemented by prefrontal cortex (PFC). This study examined how valence and attention affect the processes used for cognitive reappraisal by asking participants to passively view or to cognitively reappraise positive and negative images with full or divided attention. When participants simply viewed these images, results revealed few effects of valence or attention. However, when participants engaged in reappraisal, there was a robust effect of valence, with the reappraisal of negative relative to positive images associated with more widespread activation, including within regions of medial and lateral PFC. There also was an effect of attention, with more lateral PFC recruitment when regulating with full attention and more medial PFC recruitment when regulating with divided attention. Within two regions of medial PFC and one region of ventrolateral PFC, there was an interaction between valence and attention: in these regions, divided attention reduced activity during reappraisal of positive but not negative images. Critically, participants continued to report reappraisal success even during the Divided Attention condition. These results suggest multiple routes to successful cognitive reappraisal, depending upon image valence and the availability of attentional resources.

  15. A School Divided: One Elementary School's Response to Education Policy

    Science.gov (United States)

    Zoch, Melody

    2017-01-01

    This article examines how one elementary school was divided into two schools--a primary and an intermediate school--because of how policies were interpreted and enacted with regard to high-stakes testing. The grades in which students took high-stakes tests were privileged in terms of receiving monetary resources and support from staff. An emphasis…

  16. Theories of Learning in Educational Development: Relocating the Paradigmatic Divide.

    Science.gov (United States)

    Inglis, Alistair

    1996-01-01

    Offers a critique of a previous discussion on instructional industrialism in distance education based on instructional design. Topics include the psychological foundations of instructional design, competing paradigms in educational development, behaviorism and cognitivism, theories of learning and the paradigmatic divide, and implications for…

  17. Journalism Students, Web 2.0 and the Digital Divide

    Science.gov (United States)

    Green, Mary Elizabeth

    2009-01-01

    The purpose of this study was to find out if students were utilizing Web 2.0 applications. Since the applications in question are often employed by the media industry, the study aspired to find out if students majoring in mass communication and journalism utilized the applications more often than other students. The "digital divide" is a term used…

  18. Tamil Nadu and the Diagonal Divide in Sex Ratios

    NARCIS (Netherlands)

    A.S. Bedi (Arjun Singh); S. Srinivasan (Sharada)

    2009-01-01

    textabstractBetween 1961 and 2001, India’s 0-6 sex ratio has steadily declined. Despite evidence to the contrary, this ratio is often characterised in terms of a diagonal divide with low 0-6 sex ratios in northern and western India and normal 0-6 sex ratios in eastern and southern India. While unexp

  19. Theories of Learning in Educational Development: Relocating the Paradigmatic Divide.

    Science.gov (United States)

    Inglis, Alistair

    1996-01-01

    Offers a critique of a previous discussion on instructional industrialism in distance education based on instructional design. Topics include the psychological foundations of instructional design, competing paradigms in educational development, behaviorism and cognitivism, theories of learning and the paradigmatic divide, and implications for…

  20. Using Bloom To Bridge the WAC/WID Divide.

    Science.gov (United States)

    Cross, Geoffrey; Wills, Katherine

    A longitudinal study combined Stephen Tsuchdi's Workaday activities with Bloom's taxonomy of educational objectives to bridge the WAC/WID (writing across the curriculum/writing in the disciplines) divide. The researchers hoped that by combining concrete activities that can be applied across disciplines with a Bloomian conceptual framework of…

  1. Arc Conductance and Flow Velocity Affected by Transient Recovery Voltage

    Science.gov (United States)

    Fukuoka, Reo; Ishikawa, Yuya; Ono, Seisui; Sato, Ken; Yamamoto, Shinji; Iwao, Toru

    2016-09-01

    Recently, the stable supply of electric power is indispensable. The GCB (Gas Circuit Breaker) can prevent the spread of the fault current. However, it should have the reliability more. Therefore the GCB has been researched for performance improvement of the arc interruption of abnormal fault current without the fail. Therefore, it is important to prevent the breakdown such as the re-ignition and thermal re-ignition of arc after the arc interruption. It is necessary to reduce the arc conductance in order to prevent the re-ignition of arc. The arc conductance is derived from the temperature distribution and the volume of the arc. The temperature distribution of the arc is formed by convection. In this research, the arc conductance and flow velocity affected by transient recovery voltage are elucidated. The flow rate and temperature distribution of the arc is calculated with changing transient recovery voltage. In addition, the arc conductance is calculated in order to know the extinguish arc ability. As a result, when the transient recovery voltage increases, the probability of re-ignition increases. Therefore, the arc temperature and the arc conductance were increased.

  2. Cryocooler operation of SNIS Josephson arrays for AC Voltage standards

    Science.gov (United States)

    Sosso, A.; De Leo, N.; Fretto, M.; Monticone, E.; Roncaglione, L.; Rocci, R.; Lacquaniti, V.

    2014-05-01

    Avoiding liquid helium is now a worldwide issue, thus cryocooler operation is becoming mandatory for a wider use of superconductive electronics. Josephson voltage standards hold a peculiar position among superconducting devices, as they are in use in high precision voltage metrology since decades. Higher temperature operation would reduce the refrigerator size and complexity, however, arrays of Josephson junctions made with high temperature superconductors for voltage standard applications are not to date available. The SNIS (Superconductor-Normal metal-Insulator-Superconductor) junction technology developed at INRIM, based on low temperature superconductors, but capable of operation well above liquid helium temperature, is interesting for application to a compact cryocooled standard, allowing to set a compromise between device and refrigerator requirements. In this work, the behavior of SNIS devices cooled with a closed-cycle refrigerator has been investigated, both in DC and under RF irradiation. Issues related to thermal design of the apparatus to solve specific problems not faced with liquid coolants, like reduced cooling power and minimization of thermal gradients for uniform operation of the chip are discussed in detail.

  3. Advanced on-chip divider for monolithic microwave VCO's

    Science.gov (United States)

    Peterson, Weddell C.

    1989-01-01

    High frequency division on a monolithic circuit is a critical technology required to significantly enhance the performance of microwave and millimeter-wave phase-locked sources. The approach used to meet this need is to apply circuit design practices which are essentially 'microwave' in nature to the basically 'digital' problem of high speed division. Following investigation of several promising circuit approaches, program phase 1 culminated in the design and layout of an 8.5 GHz (Deep Space Channel 14) divide by four circuit based on a dynamic mixing divider circuit approach. Therefore, during program phase 2, an 8.5 GHz VCO with an integral divider which provides a phase coherent 2.125 GHz reference signal for phase locking applications was fabricated and optimized. Complete phase locked operation of the monolithic GaAs devices (VCO, power splitter, and dynamic divider) was demonstrated both individually and as an integrated unit. The fully functional integrated unit in a suitable test fixture was delivered to NASA for engineering data correlation. Based on the experience gained from this 8.5 GHz super component, a monolithic GaAs millimeter-wave dynamic divider for operation with an external VCO was also designed, fabricated, and characterized. This circuit, which was also delivered to NASA, demonstrated coherent division by four at an input frequency of 24.3 GHz. The high performance monolithic microwave VCO with a coherent low frequency reference output described in this report and others based on this technology will greatly benefit advanced communications systems in both the DoD and commercial sectors. Signal processing and instrumentation systems based on phase-locking loops will also attain enhanced performance at potentially reduced cost.

  4. Advanced on-chip divider for monolithic microwave VCO's

    Science.gov (United States)

    Peterson, Weddell C.

    1989-05-01

    High frequency division on a monolithic circuit is a critical technology required to significantly enhance the performance of microwave and millimeter-wave phase-locked sources. The approach used to meet this need is to apply circuit design practices which are essentially 'microwave' in nature to the basically 'digital' problem of high speed division. Following investigation of several promising circuit approaches, program phase 1 culminated in the design and layout of an 8.5 GHz (Deep Space Channel 14) divide by four circuit based on a dynamic mixing divider circuit approach. Therefore, during program phase 2, an 8.5 GHz VCO with an integral divider which provides a phase coherent 2.125 GHz reference signal for phase locking applications was fabricated and optimized. Complete phase locked operation of the monolithic GaAs devices (VCO, power splitter, and dynamic divider) was demonstrated both individually and as an integrated unit. The fully functional integrated unit in a suitable test fixture was delivered to NASA for engineering data correlation. Based on the experience gained from this 8.5 GHz super component, a monolithic GaAs millimeter-wave dynamic divider for operation with an external VCO was also designed, fabricated, and characterized. This circuit, which was also delivered to NASA, demonstrated coherent division by four at an input frequency of 24.3 GHz. The high performance monolithic microwave VCO with a coherent low frequency reference output described in this report and others based on this technology will greatly benefit advanced communications systems in both the DoD and commercial sectors. Signal processing and instrumentation systems based on phase-locking loops will also attain enhanced performance at potentially reduced cost.

  5. 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...

  6. 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.

  7. 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...

  8. 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...

  9. Simulation Research on Self-compensation Technique of Temperature-induced Scale Factor Error for Optical Voltage Sensor%光学电压互感器变比温度误差自补偿技术仿真研究

    Institute of Scientific and Technical Information of China (English)

    李传生; 荆平; 张朝阳; 孙海江

    2014-01-01

    变比温度误差是限制光学电压互感器实用化的主要因素。分析Faraday旋光器及BGO晶体线性电光系数的温度相关性对互感器变比的影响机制,提出一种基于Faraday旋光角温度特性及其对互感器变比的影响自动补偿BGO晶体电光系数温度相关性的变比误差自补偿方法。仿真结果表明:在–40+70℃,对于温度系数为0.04/℃的Faraday旋光器,当常温下Faraday旋光角在41.643.2时,变比误差在0.5%以内;当常温下Faraday旋光角为42.3时,互感器的变比误差最小,约为0.3%。要使补偿后互感器的变比误差小于0.2%,Faraday 旋光角的温度系数应小于0.03/℃。该方法为光学电压互感器变比温度误差的抑制提供新途径。%The temperature-induced scale factor error is a primary constraint on the practical applications of the optical voltage sensor (OVS). The effect mechanism of the temperature-dependent rotation angle of the Faraday rotator and the temperature-dependent linear electro-optic coefficient of the BGO crystal on the scale factor is analyzed. The method utilizing the temperature dependence of the Faraday rotator and its effect on the scale factor to self-compensate the scale factor error of the temperature-dependent electro-optic coefficient of the BGO crystal is presented. Over the temperature range from –40℃ to +70℃, if the temperature coefficient of the Faraday rotation angle is 0.04/℃, the rotation angle at room temperature must be set between 41.6 and 43.2 to ensure the scale factor error of the sensor to be within0.5%. In addition, when the rotation angle at room temperature is 42.3, the scale factor error obtains the minimum 0.3%. If the scale factor error of the sensor is required to be controlled within0.2% after compensation, the temperature coefficient of the Faraday rotation angle must be less than 0.03/℃. The proposed method offers a potential

  10. Assessment value of ECG Cornell voltage for left ventricle hypertrophy in essential hypertension patients and its correlation with cardiovascular events

    Institute of Scientific and Technical Information of China (English)

    Hua-Qin Hu; Mei Zhang; Qian Yang

    2016-01-01

    Objective:To analyze the assessment value of ECG Cornell voltage for left ventricle hypertrophy in essential hypertension patients and its correlation with cardiovascular events. Methods:A total of 118 cases of patients with essential hypertension who received inpatients treatment in our hospital from March 2013 to March 2015 were selected as the research subjects. According to ECG baseline, all included patients were divided into Cornell voltage increase group (increase ≥25%) 47 cases, no Cornell voltage change group (change < 25%) 36 cases and Cornell voltage decrease group (decrease ≥25%) 35 cases. Ultrasonic left heart indexes and serum indexes of three groups were compared, and the correlation between Cornell voltage and cardiovascular events was further analyzed.Results: Ultrasonic LVEDD, LVMI, IVSd, PWd and RWT values as well as serum uric acid, IMD, CysC, FGF23 and Hcy values of Cornell voltage decrease group were lower than those of no Cornell voltage change group and Cornell voltage increase group; ECG Cornell voltage levels in patients with essential hypertension were positively correlated with the incidence rate of cardiovascular events such as acute coronary events, sudden cardiac death and acute stroke.Conclusion: ECG Cornell voltage index can better identify the degree of left ventricle hypertrophy in patients with essential hypertension, and can be used as an independent predictor of cardiovascular events.

  11. 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...

  12. Time scales of bias voltage effects in FE/MgO-based magnetic tunnel junctions with voltage-dependent perpendicular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Lytvynenko, Ia.M. [Sumy State University, 2, Rimskogo-Korsakova Str., 40007 Sumy (Ukraine); Hauet, T., E-mail: thomas.hauet@univ-lorraine.fr [Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, 54506 Vandoeuvre les Nancy (France); Montaigne, F. [Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, 54506 Vandoeuvre les Nancy (France); Bibyk, V.V. [Sumy State University, 2, Rimskogo-Korsakova Str., 40007 Sumy (Ukraine); Andrieu, S. [Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, 54506 Vandoeuvre les Nancy (France)

    2015-12-15

    Interplay between voltage-induced magnetic anisotropy transition and voltage-induced atomic diffusion is studied in epitaxial V/Fe (0.7 nm)/ MgO/ Fe(5 nm)/Co/Au magnetic tunnel junction where thin Fe soft electrode has in-plane or out-of-plane anisotropy depending on the sign of the bias voltage. We investigate the origin of the slow resistance variation occurring when switching bias voltage in opposite polarity. We demonstrate that the time to reach resistance stability after voltage switching is reduced when increasing the voltage amplitude or the temperature. A single energy barrier of about 0.2 eV height is deduced from temperature dependence. Finally, we demonstrate that the resistance change is not correlated to a change in soft electrode anisotropy. This conclusion contrasts with observations recently reported on analogous systems. - Highlights: • Voltage-induced time dependence of resistance is studied in epitaxial Fe/MgO/Fe. • Resistance change is not related to the bottom Fe/MgO interface. • The effect is thermally activated with an energy barrier of the order of 0.2 eV height.

  13. Fundamental studies on the switching in liquid nitrogen environment using vacuum switches for application in future high-temperature superconducting medium-voltage power grids; Grundsatzuntersuchungen zum Schalten in Fluessigstickstoff-Umgebung mit Vakuumschaltern zur Anwendung in zukuenftigen Hochtemperatur-Supraleitungs-Mittelspannungsnetzen

    Energy Technology Data Exchange (ETDEWEB)

    Golde, Karsten

    2016-06-24

    By means of superconducting equipment it is possible to reduce the transmission losses in distribution networks while increasing the transmission capacity. As a result even saving a superimposed voltage level would be possible, which can put higher investment costs compared to conventional equipment into perspective. For operation of superconducting systems it is necessary to integrate all equipment in the cooling circuit. This also includes switchgears. Due to cooling with liquid nitrogen, however, only vacuum switching technology comes into question. Thus, the suitability of vacuum switches is investigated in this work. For this purpose the mechanics of the interrupters is considered first. Material investigations and switching experiments at ambient temperature and in liquid nitrogen supply information on potential issues. For this purpose, a special pneumatic construction is designed, which allows tens of thousands of switching cycles. Furthermore, the electrical resistance of the interrupters is considered. Since the contact system consists almost exclusively of copper, a remaining residual resistance and appropriate thermal losses must be considered. Since they have to be cooled back, an appropriate evaluation is given taking environmental parameters into account. The dielectric strength of vacuum interrupters is considered both at ambient temperature as well as directly in liquid nitrogen. For this purpose different contact distances are set at different interrupter types. A distinction is made between internal and external dielectric strength. Conditioning and deconditioning effects are minimized by an appropriate choice of the test circuit. The current chopping and resulting overvoltages are considered to be one of the few drawbacks of vacuum switching technology. Using a practical test circuit the height of chopping current is determined and compared for different temperatures. Due to strong scattering the evaluation is done using statistical methods. At

  14. Study on Optimization Strategy for Voltage and Reactive Power Control of Wind Farm

    Science.gov (United States)

    Lu, Q.; Shi, L.; Chen, N.

    A method for calculating reactive power limit of wind farm comprised of doubly-fed induction generators (DFIG) is proposed. The reactive power limit of wind farm is the sum of reactive power limit of DFIGs which is calculated by the method considering static stability margin. Based on this, reactive power control of wind farm is discussed and proposed. The proposed reactive power control is divided into different control modes according to power factor of high voltage side in wind farm substation and voltage of low voltage side in point of interconnection(POI). In different control modes, different control objects are applied on reactive power regulation. After reactive power regulation is finished, some reactive power of wind farm should be released. At last, numerical test system is established, the result shows that the proposed method is effective to support voltage of POI

  15. Cell-cycle regulation in green algae dividing by multiple fission.

    Science.gov (United States)

    Bišová, Kateřina; Zachleder, Vilém

    2014-06-01

    Green algae dividing by multiple fission comprise unrelated genera but are connected by one common feature: under optimal growth conditions, they can divide into more than two daughter cells. The number of daughter cells, also known as the division number, is relatively stable for most species and usually ranges from 4 to 16. The number of daughter cells is dictated by growth rate and is modulated by light and temperature. Green algae dividing by multiple fission can thus be used to study coordination of growth and progression of the cell cycle. Algal cultures can be synchronized naturally by alternating light/dark periods so that growth occurs in the light and DNA replication(s) and nuclear and cellular division(s) occur in the dark; synchrony in such cultures is almost 100% and can be maintained indefinitely. Moreover, the pattern of cell-cycle progression can be easily altered by differing growth conditions, allowing for detailed studies of coordination between individual cell-cycle events. Since the 1950s, green algae dividing by multiple fission have been studied as a unique model for cell-cycle regulation. Future sequencing of algal genomes will provide additional, high precision tools for physiological, taxonomic, structural, and molecular studies in these organisms.

  16. 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.

  17. Biophysical characterization of the fluorescent protein voltage probe VSFP2.3 based on the voltage-sensing domain of Ci-VSP

    DEFF Research Database (Denmark)

    Lundby, Alicia; Akemann, Walther; Knöpfel, Thomas

    2010-01-01

    transfer) signal. Here we report sensing current measurements from VSFP2.3, and show that VSFP2.3 carries 1.2 e sensing charges, which are displaced within 1.5 ms. The sensing currents become faster at higher temperatures, and the voltage dependence of the decay time constants is temperature dependent...

  18. 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...

  19. Role of thermal heating on the voltage induced insulator-metal transition in VO2.

    Science.gov (United States)

    Zimmers, A; Aigouy, L; Mortier, M; Sharoni, A; Wang, Siming; West, K G; Ramirez, J G; Schuller, Ivan K

    2013-02-01

    We show that the main mechanism for the dc voltage or dc current induced insulator-metal transition in vanadium dioxide VO(2) is due to local Joule heating and not a purely electronic effect. This "tour de force" experiment was accomplished by using the fluorescence spectra of rare-earth doped micron sized particles as local temperature sensors. As the insulator-metal transition is induced by a dc voltage or dc current, the local temperature reaches the transition temperature indicating that Joule heating plays a predominant role. This has critical implications for the understanding of the dc voltage or dc current induced insulator-metal transition and has a direct impact on applications which use dc voltage or dc current to externally drive the transition.

  20. Crossing of the phantom divide in modified gravity

    CERN Document Server

    Bamba, Kazuharu; Nojiri, Shin'ichi; Odintsov, Sergei D

    2009-01-01

    We reconstruct an explicit model of modified gravity in which a crossing of the phantom divide can be realized. It is shown that the Big Rip singularity appears in the model of modified gravity, whereas that the (finite-time) Big Rip singularity in modified gravity is transformed to the infinite-time singularity in the corresponding scalar field theory obtained through the conformal transformation. Furthermore, we investigate the relations between the scalar field theories realizing a crossing of the phantom divide and the corresponding modified gravitational theories by using the inverse conformal transformation. It is demonstrated that the scalar field theories describing the non-phantom phase (phantom one with the Big Rip) can be represented as the theories of real (complex) $F(R)$ gravity through the inverse (complex) conformal transformation. We also study a viable model of modified gravity in which the transition from the de Sitter universe to the phantom phase can occur.

  1. Fast image retargeting based on strip dividing and resizing

    Institute of Scientific and Technical Information of China (English)

    Shungang Hua; Honglei Wei; Tieming Su

    2014-01-01

    Based on image strip dividing, an effective and fast image retargeting algorithm is proposed for resizing images. First, we construct the image energy map using gradient magnitude of the pixels and calculate the accumulated energy of each column, dividing the image into several strips by integrating similar energy columns. The reduced amount of dimension is decided in inverse proportion to the average energy for each strip. Then we retar-get the image combining scaling with cropping in terms of each strip’s reduced ratio. Experiment results show that the proposed algorithm is capable of implementing fast image retargeting and preserving both the local structures and the global visual effect of the image.

  2. Clobazam single or divided dose against diazepam in anxiety neurosis.

    Science.gov (United States)

    Channabasavanna, S M; Pinto Pereira, L M

    1986-01-01

    One-hundred-and-fifteen patients diagnosed as anxiety neurotics randomly received in a double blind study 20 mg clobazam (Frisium) as a single nightly dose (37 patients) or 10 mg b.d. (38 patients) or diazepam 5 mg b.d. (40 patients) for six weeks, followed by two weeks on placebo. Both the single and divided doses of clobazam were therapeutically equivalent to diazepam. After drug withdrawal, all three treatment groups continued to improve. Patients on clobazam showed better motor performance than the diazepam series. Patients on clobazam divided dose performed significantly better than those on diazepam. Minor side-effects occurred in all patients. From the results clobazam as a single dose of 20 mg has good anxiolysis without any hungover effect.

  3. Divided-aperture differential confocal fast-imaging microscopy

    Science.gov (United States)

    Wang, Yun; Qiu, Lirong; Zhao, Xiangye; Zhao, Weiqian

    2017-03-01

    A new method, laser divided-aperture differential confocal microscopy (DDCM), is proposed to achieve high-resolution 3D imaging of microstructures of large-scale sample surfaces. This method uses a divided-aperture confocal structure to significantly improve the axial resolution of confocal microscopy and keep a long working distance simultaneously; uses two radically offset point detectors to achieve differential detection to further improve the axial response sensitivity and realize fast imaging of a large-scale sample surface with a big axial scan-step interval. Theoretical analyses and experimental results show that the DDCM can reach an axial resolution of 5 nm with a 3.1 mm working distance with a 3 times imaging speed of a confocal system with the same resolution.

  4. Multiple-resolution clustering for recursive divide and conquer

    Science.gov (United States)

    Noel, Steven E.; Szu, Harold H.

    1997-04-01

    In recent work, a recursive divide-and-conquer approach was developed for path-minimization problems such as the traveling salesman problem (TSP). The approach is based on multiple-resolution clustering to decompose a problem into minimally-dependent parts. It is particularly effective for large-scale, fractal data sets, which exhibit clustering on all scales, and hence at all resolutions. This leads to the application of wavelets for performing the necessary multiple-resolution clustering. While the general topic of multiple-resolution clustering via wavelets is relatively immature, it has been explored for certain specific applications. However, nothing in the literature addresses the specific type of multiple-resolution clustering needed for the divide-and-conquer approach. That is the primary goal of this paper.

  5. A Divide-and-Conquer Strategy for Parsing

    CERN Document Server

    Shiuan, P L; Shiuan, Peh Li; Ann, Christopher Ting Hian

    1996-01-01

    In this paper, we propose a novel strategy which is designed to enhance the accuracy of the parser by simplifying complex sentences before parsing. This approach involves the separate parsing of the constituent sub-sentences within a complex sentence. To achieve that, the divide-and-conquer strategy first disambiguates the roles of the link words in the sentence and segments the sentence based on these roles. The separate parse trees of the segmented sub-sentences and the noun phrases within them are then synthesized to form the final parse. To evaluate the effects of this strategy on parsing, we compare the original performance of a dependency parser with the performance when it is enhanced with the divide-and-conquer strategy. When tested on 600 sentences of the IPSM'95 data sets, the enhanced parser saw a considerable error reduction of 21.2% in its accuracy.

  6. A Novel Nanometric Reversible Signed Divider with Overflow Checking Capability

    Directory of Open Access Journals (Sweden)

    Faraz Dastan

    2012-03-01

    Full Text Available One of the best approaches for designing future computers is that we use reversible logic. Reversible logic circuits have lower power consumption than the common circuits, used in computers nowadays. In this study we propose a new reversible division circuit. This reversible division circuit is signed divider and has an overflow checking capability. Among the designed and proposed reversible division circuits, our proposed division circuit is the first reversible signed divider with overflow checking capability which has been designed. In this circuit we use some reversible components like reversible parallel adder, reversible left-shift register, reversible multiplexer, reversible n-bit register and reversible n-bit register with parallel load line. In this paper all the scales are in the nanometric area.

  7. 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.    .

  8. Voltage controlled terahertz transmission through GaN quantum wells

    OpenAIRE

    Laurent, T.; Sharma, R.; Torres, J.; Nouvel, P; Blin, S.; Varani, L.; Cordier, Y.; Chmielowska, M.; Chenot, S.; Faurie, JP; Beaumont, B.; P. Shiktorov; Starikov, E.; Gruzinskis, V.; Korotyevyev, V.

    2011-01-01

    We report measurements of radiation transmission in the 0.220--0.325 THz frequency domain through GaN quantum wells grown on sapphire substrates at room and low temperatures. A significant enhancement of the transmitted beam intensity with the applied voltage on the devices under test is found. For a deeper understanding of the physical phenomena involved, these results are compared with a phenomenological theory of light transmission under electric bias relating the transmission enhancement ...

  9. Crossing of Phantom Divide in $F(R)$ Gravity

    CERN Document Server

    Bamba, Kazuharu; Nojiri, Shin'ichi; Odintsov, Sergei D

    2010-01-01

    An explicit model of $F(R)$ gravity with realizing a crossing of the phantom divide is reconstructed. In particular, it is shown that the Big Rip singularity may appear in the reconstructed model of $F(R)$ gravity. Such a Big Rip singularity could be avoided by adding $R^2$ term or non-singular viable $F(R)$ theory to the model because phantom behavior becomes transient.

  10. Histological findings of divided muscle after peroral endoscopic myotomy

    OpenAIRE

    Shiwaku, Hironari; Inoue, Haruhiro; Nimura, Satoshi; Yamashita, Kanefumi; Ohmiya, Toshihiro; Takeno, Shinsuke; Sasaki, Takamitsu; Yamashita, Yuichi

    2016-01-01

    Peroral endoscopic myotomy (POEM) is a revolutionary therapy for achalasia and related disorders. POEM utilizes almost the same myotomy procedure as the Heller myotomy; thus, it would be expected to have the same or greater duration of therapeutic effect. However, to date, there have been no reports to prove the basis for this procedure in achalasia. In this case, we were able to histologically show the divided muscle after POEM since the patient had an esophagectomy for esophageal cancer. Hi...

  11. Dividing Streamline Formation Channel Confluences by Physical Modeling

    Directory of Open Access Journals (Sweden)

    Minarni Nur Trilita

    2010-02-01

    Full Text Available Confluence channels are often found in open channel network system and is the most important element. The incoming flow from the branch channel to the main cause various forms and cause vortex flow. Phenomenon can cause erosion of the side wall of the channel, the bed channel scour and sedimentation in the downstream confluence channel. To control these problems needed research into the current width of the branch channel. The incoming flow from the branch channel to the main channel flow bounded by a line distributors (dividing streamline. In this paper, the wide dividing streamline observed in the laboratory using a physical model of two open channels, a square that formed an angle of 30º. Observations were made with a variety of flow coming from each channel. The results obtained in the laboratory observation that the width of dividing streamline flow is influenced by the discharge ratio between the channel branch with the main channel. While the results of a comparison with previous studies showing that the observation in the laboratory is smaller than the results of previous research.

  12. FLOOD ROUTING MODELS IN CONFLUENT AND DIVIDING CHANNELS

    Institute of Scientific and Technical Information of China (English)

    范平; 李家春; 刘青泉

    2004-01-01

    By introducing a water depth connecting formula, the hydraulic equations in the dividing channel system were coupled and the relation of discharge distribution between the branches of the dividing channels can be yielded. In this manner, a numerical model for the confluent channels was established to study the variation of backwater effects with the parameters in the channel junction. The meeting of flood peaks in the mainstream and tributary can be analyzed with this model. The flood peak meeting is found to be a major factor for the extremely high water level in the mainstream during the 1998 Yangtze River flood. Subsequently the variations of discharge distribution and water level with channel parameters between each branch in this system were studied as well. As a result, flood evolution caused by Jingjiang River shortcut and sediment deposition in the entrance of dividing channels of the Yangtze River may be qualitatively elucidated. It is suggested to be an effective measure for flood mitigation to enhance regulation capability of reservoirs available upstream of the tributaries and harness branch entrance channels.

  13. A transient divided-bar method for simultaneous measurements of thermal conductivity and thermal diffusivity

    DEFF Research Database (Denmark)

    Bording, Thue Sylvester; Nielsen, Søren Bom; Balling, Niels

    2016-01-01

    Accurate information on thermal conductivity and thermal diffusivity of materials is of central importance in relation to geoscience and engineering problems involving the transfer of heat. Within the geosciences, this applies to all aspects regarding the determination of terrestrial heat flow...... and volumetric heat capacity, and thereby also thermal diffusivity, are measured simultaneously. As the density of samples is easily determined independently, specific heat capacity may also be determined. Finite element formulation provides a flexible forward solution for heat transfer across the bar...... and subsurface temperature modelling. Several methods, including the classical divided-bar technique, are available for laboratory measurements of thermal conductivity, and much fewer for thermal diffusivity. We have generalized the divided-bar technique to the transient case, in which thermal conductivity...

  14. A transient divided-bar method for simultaneous measurements of thermal conductivity and thermal diffusivity

    DEFF Research Database (Denmark)

    Bording, Thue Sylvester; Nielsen, Søren Bom; Balling, Niels

    2016-01-01

    Accurate information on thermal conductivity and thermal diffusivity of materials is of central importance in relation to geoscience and engineering problems involving the transfer of heat. Within the geosciences, this applies to all aspects regarding the determination of terrestrial heat flow...... and subsurface temperature modelling. Several methods, including the classical divided-bar technique, are available for laboratory measurements of thermal conductivity, and much fewer for thermal diffusivity. We have generalized the divided-bar technique to the transient case, in which thermal conductivity...... and volumetric heat capacity, and thereby also thermal diffusivity, are measured simultaneously. As the density of samples is easily determined independently, specific heat capacity may also be determined. Finite element formulation provides a flexible forward solution for heat transfer across the bar...

  15. Reactive dividing wall column for hydrolysis of methyl acetate:Design and control☆

    Institute of Scientific and Technical Information of China (English)

    Lumin Li; Lanyi Sun; Delian Yang; Wang Zhong; Yi Zhu; Yuanyu Tian

    2016-01-01

    Reactive distillation and dividing wall column distillation are two kinds of effective separation technologies, and their integrated configuration, reactive dividing wall column (RDWC), presents attractive advantages. In this study, the rigorous simulation of RDWC for methyl acetate hydrolysis is performed, and sensitivity analysis is conducted to obtain the minimum reboiler duty. Then a comparison is made between the conventional process and RDWC process, and it shows that 20.1%energy savings can be achieved by RDWC process. In addition, the dynamic characteristic of RDWC is studied and an effective control strategy is proposed. The simple PI control scheme with three temperature loops can obtain reasonable control performance and maintain products at de-sired purities. It is proved that this RDWC process is an energy efficiency alternative with good controllability. © 2016 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. Al rights reserved.

  16. Reversible voltage dependent transition of abnormal and normal bipolar resistive switching

    Science.gov (United States)

    Wang, Guangyu; Li, Chen; Chen, Yan; Xia, Yidong; Wu, Di; Xu, Qingyu

    2016-11-01

    Clear understanding the mechanism of resistive switching is the important prerequisite for the realization of high performance nonvolatile resistive random access memory. In this paper, binary metal oxide MoOx layer sandwiched by ITO and Pt electrodes was taken as a model system, reversible transition of abnormal and normal bipolar resistive switching (BRS) in dependence on the maximum voltage was observed. At room temperature, below a critical maximum voltage of 2.6 V, butterfly shaped I-V curves of abnormal BRS has been observed with low resistance state (LRS) to high resistance state (HRS) transition in both polarities and always LRS at zero field. Above 2.6 V, normal BRS was observed, and HRS to LRS transition happened with increasing negative voltage applied. Temperature dependent I-V measurements showed that the critical maximum voltage increased with decreasing temperature, suggesting the thermal activated motion of oxygen vacancies. Abnormal BRS has been explained by the partial compensation of electric field from the induced dipoles opposite to the applied voltage, which has been demonstrated by the clear amplitude-voltage and phase-voltage hysteresis loops observed by piezoelectric force microscopy. The normal BRS was due to the barrier modification at Pt/MoOx interface by the accumulation and depletion of oxygen vacancies.

  17. 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....

  18. 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....

  19. Comparison of Harmony Search Algorithm and Particle Swarm Optimization for Distributed Generation Allocation to Improve Steady State Voltage Stability of Distribution Networks

    Directory of Open Access Journals (Sweden)

    Hamed Piarehzadeh

    2012-08-01

    Full Text Available In this study is tried to optimal distributed generation allocation for stability improvement in radial distribution systems. Voltage instability implies an uncontrolled decrease in voltage triggered by a disturbance, leading to voltage collapse and is primarily caused by dynamics connected with the load. The instability is divided into steady state and transient voltage instability Based on the time spectrum of the incident of the phenomena. The analysis is accomplished using a steady state voltage stability index which can be evaluated at each node of the distribution system. Several optimal capacities and locations are used to check these results. The location of DG has the main effect voltage stability on the system. Effects of location and capacity on incrementing steady state voltage stability in radial distribution systems are examined through Harmony Search Algorithm (HSA and finally the results are compared to Particle Swarm Optimization (PSO on the terms of speed, convergence and accuracy.

  20. 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.

  1. 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.

  2. Implementation of Dividing Cubes Algorithm Based on CUDA%基于 CUDA 的 Dividing Cubes 算法实现

    Institute of Scientific and Technical Information of China (English)

    张文波; 曹耀钦; 孙伟; 李海龙

    2013-01-01

    In traditional Dividing Cubes algorithm ,voxels are divided into many small elements in one time which bring a large number of calculations .Therefore ,a progressive subdivision is proposed to reduce calculations .In the meanwhile ,the algorithm is transplanted into GPU , and implemented based on CUDA . The kernel , thread organization and memory allocation is also designed .Experimental results show that almost 10 times speedup is reached by using GPU′s parallel acceleration capacity .%针对传统Dividing Cubes算法中一次性将体元剖分为较小体元而带来大量计算的问题,提出递进式的体元剖分方式,以减少剖分过程中的计算量。同时,将算法移植到图形处理器(GPU )上执行,在统一计算设备架构(CUDA )下对其进行实现,并分别对 kernel函数、线程结构和存储空间进行了设计和分配。实验结果表明,利用GPU的并行加速能力可以达到将近10倍的加速比,有效地提升了等值面的绘制速度。

  3. 金属氧化物限压器冷却结构设计及其三维温度场仿真分析%Cooling Structure Design of Metal Oxide Voltage Limiter and Simulation Study of Its Three Dimensional Temperature Field

    Institute of Scientific and Technical Information of China (English)

    温惠; 谭震宇; 唐宗华; 孙树敏; 李庆民

    2011-01-01

    During the short-circuit fault in power system,a huge short-circuit energy will inject into metal oxide voltage limiter(MO) mandrel,leading to the rapid temperature rise of MOV.To ensure the reliable running of MOV and to extend its service life,MOV needs to cool as soon as possible.Therefore,MOV cooling structure with the excellent cooling efficiency and the knowledge for the temperature distributions of MOV mandrel are of essential importance.We proposed a new cooling structure of MOV,and established a finite element model of MOV 3D temperature field based on the theory of heat transfer.For the proposed cooling structure of MOV and the calculation model,the systematical calculations and analyses of the influences of the diameter,numbers and distributions of the cooling channel on the heat transfer were performed using the finite element software ANSYS.It is shown that the efficiency of the cooling structure can be changed by changing its diameter,there is an optimum diameter of 10 mm,where the good cooling efficiency is obtained,and the efficiency of cooling structure with the four channels is superior to that with the two channels.%电力系统发生短路故障时,巨大的短路能量注入到金属氧化物限压器(metal oxide voltage limiter,MOV)上,导致其温度快速升高。为保证MOV的可靠运行,延长其使用寿命,需要尽快散热降温。因此,MOV冷却结构的设计和了解MOV的温度分布非常重要。为此,提出了一种新型MOV冷却结构,并基于传热学的理论建立了MOV三维温度场有限元法计算模型。用有限元计算软件ANSYS系统地计算分析了MOV冷却通道的直径、条数和分布等几何量对于通风道内传热特性的影响。结果表明:这种新型冷却结构的MOV要比传统MOV的散热能力更好,MOV散热能力随冷却通道直径不同而变化,通道直径存在约10 mm的最优值,此时冷却结构散热效果较好,4条冷却通道比2条冷却通道具有更好的散热效果。

  4. 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.

  5. Electronic Current Transducer (ECT) for high voltage dc lines

    Science.gov (United States)

    Houston, J. M.; Peters, P. H., Jr.; Summerayes, H. R., Jr.; Carlson, G. J.; Itani, A. M.

    1980-02-01

    The development of a bipolar electronic current transducer (ECT) for measuring the current in a high voltage dc (HVDC) power line at line potential is discussed. The design and construction of a free standing ECT for use on a 400 kV line having a nominal line current of 2000 A is described. Line current is measured by a 0.0001 ohm shunt whose voltage output is sampled by a 14 bit digital data link. The high voltage interface between line and ground is traversed by optical fibers which carry digital light signals as far as 300 m to a control room where the digital signal is converted back to an analog representation of the shunt voltage. Two redundant electronic and optical data links are used in the prototype. Power to operate digital and optical electronics and temperature controlling heaters at the line is supplied by a resistively and capacitively graded 10 stage cascade of ferrite core transformers located inside the hollow, SF6 filled, porcelain support insulator. The cascade is driven by a silicon controlled rectifier inverter which supplies about 100 W of power at 30 kHz.

  6. A fiber optic hybrid multifunctional AC voltage sensor

    Energy Technology Data Exchange (ETDEWEB)

    Sokolovsky, A.; Zadvornov, S. [IRE, Moscow (Russian Federation); Ryabko, M. [UFD, Moscow (Russian Federation)

    2008-07-01

    Hybrid sensors have the advantages of both electronic and optical technologies. Their sensing element is based on conventional transducers and the optical fiber is used as a transmission media for the optical signal encoded with information between the local module and the remote module. The power supply for the remote module is usually provided by a built-in photoelectric converter illuminated by the optical radiation going through the same or another optical fiber. Electro-optic hybrid sensors have been widely used because of the electrical isolation provided by optical fiber. In the conventional fiber optic voltage sensor, piezoelectric or electro-optic transducers are implemented. Processing and conditioning measurement information is a complex task in these sensors. Moreover, the considerable drawback of most of these systems is that only one parameter, usually voltage value, is measured. This paper presented a novel fiber optic hybrid sensor for alternating current voltage measurements. This instrument provides the simultaneous measurement of four parameters, notably voltage value, frequency, phase angle and the external temperature. The paper described the measurement technology of the instrument including the remote module and optical powering as well as the unique modulation algorithm. The results and conclusions were also presented. 7 refs., 4 figs.

  7. Current–voltage characteristics of manganite–titanite perovskite junctions

    Directory of Open Access Journals (Sweden)

    Benedikt Ifland

    2015-07-01

    Full Text Available After a general introduction into the Shockley theory of current voltage (J–V characteristics of inorganic and organic semiconductor junctions of different bandwidth, we apply the Shockley theory-based, one diode model to a new type of perovskite junctions with polaronic charge carriers. In particular, we studied manganite–titanate p–n heterojunctions made of n-doped SrTi1−yNbyO3, y = 0.002 and p-doped Pr1−xCaxMnO3, x = 0.34 having a strongly correlated electron system. The diffusion length of the polaron carriers was analyzed by electron beam-induced current (EBIC in a thin cross plane lamella of the junction. In the J–V characteristics, the polaronic nature of the charge carriers is exhibited mainly by the temperature dependence of the microscopic parameters, such as the hopping mobility of the series resistance and a colossal electro-resistance (CER effect in the parallel resistance. We conclude that a modification of the Shockley equation incorporating voltage-dependent microscopic polaron parameters is required. Specifically, the voltage dependence of the reverse saturation current density is analyzed and interpreted as a voltage-dependent electron–polaron hole–polaron pair generation and separation at the interface.

  8. Step voltage transient currents in poly(vinylidene fluoride)

    Science.gov (United States)

    Kaura, T.; Nath, Rabinder

    1983-10-01

    The step voltage current transient characteristics have been studied in poly(vinylidene flouride) as a function of field, temperature, and time. The current peaks have been observed in the current-time characteristics. These peaks have been attributed to the space-charge injection phenomena. Using the space-charge-limited model of current transients the mobility has been estimated to 2.2±0.2×10-9 cm2 v-1 s-1 at 301 K. The analysis of the temperature dependence of mobilities establishes that charge carrier transport in extended states involving trapping is predominant.

  9. An AMOLED AC-Biased Pixel Design Compensating the Threshold Voltage and I-R Drop

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2011-01-01

    Full Text Available We propose a novel pixel design and an AC bias driving method for active-matrix organic light-emitting diode (AM-OLED displays using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs. The proposed threshold voltage and I-R drop compensation circuit, which comprised three transistors and one capacitor, have been verified to supply uniform output current by simulation work using the Automatic Integrated Circuit Modeling Simulation Program with Integrated Circuit Emphasis (AIM-SPICE simulator. The simulated results demonstrate excellent properties such as low error rate of OLED anode voltage variation (<0.7% and low voltage drop of VDD power line. The proposed pixel circuit effectively enables threshold-voltage-deviation correction of driving TFT and compensates for the voltage drop of VDD power line using AC bias on OLED cathode.

  10. Temperature Characteristics of BJMOSFET

    Institute of Scientific and Technical Information of China (English)

    ZENG Yun; YAN Min; YANG Hong-guan; GAO Yun

    2005-01-01

    The resolution expression for the temperature dependence of the current and threshold voltage is deduced as well as the analysis of temperature characteristics of BJMOSFET. Equivalent circuit of analysis and simulation has been established for the BJMOSFET temperature characteristics. By using the general circuit simulation software of PSpice9 and computer simulation, characteristic graphs of the BJMOSFET output characteristic, transient characteristic and amplitude-frequency characteristic with temperature variation are obtained. The results accorded very good with theoretical analysis and proved that BJMOSFET has better temperature characteristics than traditional MOSFET.

  11. 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.

  12. 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

  13. 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.

  14. BRIDGING THE KNOWLEDGE DIVIDE Educational Technology for Development

    OpenAIRE

    2009-01-01

    BRIDGING THE KNOWLEDGE DIVIDEEducational Technology for DevelopmentMarshall,S., Kinuthia, W. & Wallace Taylor., Ed.D.; Information Age Publishing, Charlotte, NC, SBN: 978-1-60752-109-9, p.433, 2009Reviewed by Ozlem OZANFaculty of EducationEskişehir Osmangazi UniversityEskisehir, TURKEYThe concept of a knowledge divide is used to describe the gap in living conditions between those who can find, manage and process information or knowledge, and those who are impaired in this, for one reason or a...

  15. Affinity and Hostility in Divided Communities: a Mathematical Model

    CERN Document Server

    Thron, Christopher

    2015-01-01

    We propose, develop, and analyze a mathematical model of intergroup attitudes in a community that is divided between two distinct social groups (which may be distinguished by religion, ethnicity, or some other socially distinguishing factor). The model is based on very simple premises that are both intuitive and justified by sociological research. We investigate the behavior of the model in various special cases, for various model configurations. We discuss the stability of the model, and the continuous or discontinuous dependence of model behavior on various parameters. Finally, we discuss possible implications for strategies to improve intergroup affinity, and to defuse tension and prevent deterioration of intergroup relationships.

  16. Observations favor the crossing of phantom divide lines

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Using three different parameterized dark energy models, we reconstruct the properties of dark energy from the latest 397 Sne Ia, CMB and BAO with the present matter density, Ωm0, given prior. We find that, when Ωm0 is not small, for example, Ωm0 = 0.28 or 0.32, an evolving dark energy with a crossing of phantom divide line is favored and this conclusion seems to be model independent. We also find that the evolving properties of dark energy become more and more evident with the increase of Ωm0 given prior.

  17. Blurring of the public/private divide: the Canadian chapter.

    Science.gov (United States)

    Flood, Colleen M; Thomas, Bryan

    2010-06-01

    Blurring of public/private divide is occurring in different ways around the world, with differential effects in terms of access and equity. In Canada, one pathway towards privatization has received particular attention: duplicative private insurance, allowing those with the financial means to bypass queues in the public system. We assess recent legal and policy developments on this front, but also describe other trends towards the blurring of public and private in Canada: the reliance on mandated private insurance for pharmaceutical coverage; provincial governments' reliance on public-private partnerships to finance hospitals; and the incorporation of for-profit clinics within the public health care system.

  18. The NCI Digital Divide Pilot Projects: implications for cancer education.

    Science.gov (United States)

    Kreps, Gary L; Gustafson, David; Salovey, Peter; Perocchia, Rosemarie Slevin; Wilbright, Wayne; Bright, Mary Anne; Muha, Cathy

    2007-01-01

    The National Cancer Institute (NCI) supported four innovative demonstration research projects, "The Digital Divide Pilot Projects," to test new strategies for disseminating health information via computer to vulnerable consumers. These projects involved active research collaborations between the NCI's Cancer Information Service (CIS) and regional cancer control researchers to field test new approaches for enhancing cancer communication in vulnerable communities. The projects were able to use computers to successfully disseminate relevant cancer information to vulnerable populations. These demonstration research projects suggested effective new strategies for using communication technologies to educate underserved populations about cancer prevention, control, and care.

  19. Digital Television, Convergence, and the Public: Another Digital Divide?

    Directory of Open Access Journals (Sweden)

    Jason Smith

    2009-06-01

    Full Text Available While 85 percent of Americans pay to receive television signals through satellite or cable companies, 15 percent still receive their television using over-the-air signals. With the elminination of analog television signals, the 15 percent of households have had to make significant changes in their viewing technology. These households tend to be elderly, poor, minority and rural. Signal coverage areas will be cut back, since government assumed a viewer would have an antenna on a 30 foot pole. Few do, and governmental programs delibertely hid this engineering fact. It is argued that digitalism has neglected the public use of the airways and created yet one more digital divide.

  20. Korean Nationalism in a Divided Nation: Challenges to US Policy

    OpenAIRE

    Olsen, Edward A.

    2008-01-01

    The article of record as published may be found at http://dx.doi.org/10.1111/j.1976-5118.2008.00002.x Korean nationalism poses challenges for Koreans dwelling in each half of the divided Korean nation because each half of the nation must simultaneously deal with both their own and the other half’s form of semi-nationalism and also with peninsular pan-nationalism. Coping with these three forms of nationalism is also a problem for US policy toward each Korean state and toward ...

  1. CLOBAZAM SINGLE OR DIVIDED DOSE AGAINST DIAZEPAM IN ANXIETY NEUROSIS

    OpenAIRE

    1986-01-01

    SUMMARY One-hundred-and-fifteen patients diagnosed as anxiety neurotics randomly received in a double blind study 20 mg clobazam (Frisium) as a single nightly dose (37 patients) or 10 mg b.d. (38 patients) or diazepam 5 mg b.d. (40 patients) for six weeks, followed by two weeks on placebo. Both the single and divided doses of clobazam were therapeutically equivalent to diazepam. After drug withdrawal, all three treatment groups continued to improve. Patients on clobazam showed better motor pe...

  2. Traffic Prediction Based on SVM Training Sample Divided by Time

    Directory of Open Access Journals (Sweden)

    Lingli Li

    2013-07-01

    Full Text Available In recent years, the volume of traffic is rapidly increasing. When vehicles running through the tunnel are more intensive or move slowly, the tunnel environment occurs deteriorated sharply, which affects the normal operation of the vehicle in the tunnel. This paper uses the result of previous mining association rules to select feature items and to establish four training samples divided by time. Then the training samples are utilized to create the SVM classification model. Finally the trained SVM model is used to prediction the tunnel traffic situation. Through traffic situation prediction, effective decisions can be made before traffic jams, and ensure that the tunnel traffic is normal.  

  3. Transition duct with divided upstream and downstream portions

    Energy Technology Data Exchange (ETDEWEB)

    McMahan, Kevin Weston; LeBegue, Jeffrey Scott; Maldonado, Jaime Javier; Dillard, Daniel Jackson; Flanagan, James Scott

    2015-07-14

    Turbine systems are provided. In one embodiment, a turbine system includes a transition duct comprising an inlet, an outlet, and a duct passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The duct passage includes an upstream portion extending from the inlet and a downstream portion extending from the outlet. The turbine system further includes a rib extending from an outer surface of the duct passage, the rib dividing the upstream portion and the downstream portion.

  4. 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....

  5. 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...

  6. 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...

  7. 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.

  8. 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.

  9. Improvement of the characteristics of inductive dividers due to the use of electronic devices; Mejora en las caracteristicas de divisores inductivos mediante el uso de dispositivos electronicos

    Energy Technology Data Exchange (ETDEWEB)

    Slomovitz, Daniel [UTE - Laboratorio, Montevideo (Uruguay)

    1996-12-31

    This work present a new system of electronic compensation for decrease the errors of inductive dividers and measure transformers of voltage. A auxiliary current amplifier reduce the magnetization current, main source of errors in this devices, in low frequency. Simultaneously rise the input impedance. This method permit the construction of small devices, few weight and little errors, without overload in the input circuits that is connected 5 refs., 1 fig., 2 tabs.

  10. Mechanisms of Organelle Inheritance in Dividing Plant Cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Organelles form essential compartments of all eukaryotic cells. Mechanisms that ensure the unbiased inheritance of organelles during cell division are therefore necessary to maintain the viability of future cell generations. Although inheritance of organelles represents a fundamental component of the cell cycle, surprisingly little is known about the underlying mechanisms that facilitate unbiased organelle inheritance. Evidence from a select number of studies, however,indicates that ordered organelle inheritance strategies exist in dividing cells of higher plants. The basic requirement for unbiased organelle inheritance is the duplication of organelle volume and distribution of the resulting organelle populations in a manner that facilitates unbiased partitioning of the organelle population to each daughter cell. Often, partitioning strategies are specific to the organelle, being influenced by the functional requirements of the organelle and whether the cells are mitotically active or re-entering into the cell cycle. Organelle partitioning mechanisms frequently depend on interactions with either the actin or microtubule cytoskeleton. In this focused review, we attempt to summarize key findings regarding organelle partitioning strategies in dividing cells of higher plants. We particularly concentrate on the role of the cytoskeleton in mediating unbiased organelle partitioning.

  11. A divide and conquer approach to multiple alignment.

    Science.gov (United States)

    Dress, A; Füllen, G; Perrey, S

    1995-01-01

    We present a report on work in progress on a divide and conquer approach to multiple alignment. The algorithm makes use of the costs calculated from applying the standard dynamic programming scheme to all pairs of sequences. The resulting cost matrices for pairwise alignment give rise to secondary matrices containing the additional costs imposed by fixing the path through the dynamic programming graph at a particular vertex. Such a constraint corresponds to a division of the problem obtained by slicing both sequences between two particular positions, and aligning the two sequences on the left and the two sequences on the right, charging for gaps introduced at the slicing point. To obtain an estimate for the additional cost imposed by forcing the multiple alignment through a particular vertex in the whole hypercube, we will take a (weighted) sum of secondary costs over all pairwise projections of the division of the problem, as defined by this vertex, that is, by slicing all sequences at the points suggested by the vertex. We then use that partition of every single sequence under consideration into two 'halfs' which imposes a minimal (weighted) sum of pairwise additional costs, making sure that one of the sequences is divided somewhere close to its midpoint. Hence, each iteration can cut the problem size in half. As the enumeration of all possible partitions may restrict this approach to small-size problems, we eliminate futile partitions, and organize their enumeration in a way that starts with the most promising ones.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Is there a second level divide in students Internet skills?

    DEFF Research Database (Denmark)

    Dau, Susanne; Purushothaman, Aparna

    2015-01-01

    The concept of digital divide have moved beyond physical disparities in usage and also encompasses issues impending access like human (skills) social, cultural, and psychological barriers that affect the usage of existing available technologies apart from ownership. This paper focuses on the insu......The concept of digital divide have moved beyond physical disparities in usage and also encompasses issues impending access like human (skills) social, cultural, and psychological barriers that affect the usage of existing available technologies apart from ownership. This paper focuses...... on the insufficient level of skills which students have in making the best use of available Internet technology. Varying online skills of the students in higher education from two countrywide scenarios - Denmark and India are discussed. The paper emphasizes on the reflective and conceptual issues which the students...... is illuminated from different perspectives in the context of two countries which has contrasting socio-economic environment, ICT development and network connectivity. The paper´s brings insights on how different types of literacy skills influence students successful access to relevant online learning...

  13. Stratified Flow Past a Hill: Dividing Streamline Concept Revisited

    Science.gov (United States)

    Leo, Laura S.; Thompson, Michael Y.; Di Sabatino, Silvana; Fernando, Harindra J. S.

    2016-06-01

    The Sheppard formula (Q J R Meteorol Soc 82:528-529, 1956) for the dividing streamline height H_s assumes a uniform velocity U_∞ and a constant buoyancy frequency N for the approach flow towards a mountain of height h, and takes the form H_s/h=( {1-F} ) , where F=U_{∞}/Nh. We extend this solution to a logarithmic approach-velocity profile with constant N. An analytical solution is obtained for H_s/h in terms of Lambert-W functions, which also suggests alternative scaling for H_s/h. A `modified' logarithmic velocity profile is proposed for stably stratified atmospheric boundary-layer flows. A field experiment designed to observe H_s is described, which utilized instrumentation from the spring field campaign of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program. Multiple releases of smoke at F≈ 0.3-0.4 support the new formulation, notwithstanding the limited success of experiments due to logistical constraints. No dividing streamline is discerned for F≈ 10, since, if present, it is too close to the foothill. Flow separation and vortex shedding is observed in this case. The proposed modified logarithmic profile is in reasonable agreement with experimental observations.

  14. The digital divide phenomenon in a hand surgery outpatient clinic.

    Science.gov (United States)

    Parekh, Selene G; Sodha, Samir; McGuire, Kevin J; Bozentka, David J; Rozental, Tamara D; Beredjiklian, Pedro K

    2004-04-01

    The Internet has become an important source of medical information for patients. However, the availability of this resource for individuals in the lower socioeconomic groups is limited, a concept termed the digital divide. To evaluate this phenomenon, we conducted a survey study to quantify the accessibility and use of the Internet for obtaining medical information in an outpatient hand surgery clinic population. A 28-question survey was distributed to 207 patients concerning computer accessibility, Internet use for medical and nonmedical information, Internet trust and security, and patient economic demographics. After analysis of the data, we found individuals in households with higher incomes had a greater likelihood of owning computers than those in lower income brackets. As income increases, the time spent on the Internet also increases. Another statistically significant trend was that higher income patient households thought that Internet information was trustworthy, secure, and private compared with the lower income brackets. We concluded that clinical settings where the predominant patient population earns less than $18,000 may not benefit or use physician Internet-based services or information. The concept of the digital divide seems to be a real phenomenon in the clinical practice of orthopaedics.

  15. On a nonlinear Kalman filter with simplified divided difference approximation

    KAUST Repository

    Luo, Xiaodong

    2012-03-01

    We present a new ensemble-based approach that handles nonlinearity based on a simplified divided difference approximation through Stirling\\'s interpolation formula, which is hence called the simplified divided difference filter (sDDF). The sDDF uses Stirling\\'s interpolation formula to evaluate the statistics of the background ensemble during the prediction step, while at the filtering step the sDDF employs the formulae in an ensemble square root filter (EnSRF) to update the background to the analysis. In this sense, the sDDF is a hybrid of Stirling\\'s interpolation formula and the EnSRF method, while the computational cost of the sDDF is less than that of the EnSRF. Numerical comparison between the sDDF and the EnSRF, with the ensemble transform Kalman filter (ETKF) as the representative, is conducted. The experiment results suggest that the sDDF outperforms the ETKF with a relatively large ensemble size, and thus is a good candidate for data assimilation in systems with moderate dimensions. © 2011 Elsevier B.V. All rights reserved.

  16. 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.

  17. The world's first high voltage GaN-on-Diamond power semiconductor devices

    Science.gov (United States)

    Baltynov, Turar; Unni, Vineet; Narayanan, E. M. Sankara

    2016-11-01

    This paper presents the detailed fabrication method and extensive electrical characterisation results of the first-ever demonstrated high voltage GaN power semiconductor devices on CVD Diamond substrate. Fabricated circular GaN-on-Diamond HEMTs with gate-to-drain drift length of 17 μm and source field plate length of 3 μm show an off-state breakdown voltage of ∼1100 V. Temperature characterisation of capacitance-voltage characteristics and on-state characteristics provides insight on the temperature dependence of key parameters such as threshold voltage, 2DEG sheet carrier concentration, specific on-state resistance, and drain saturation current in the fabricated devices.

  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. Connection for transfer of Liquid Nitrogen from High Voltage to ground potential

    DEFF Research Database (Denmark)

    Rasmussen, Claus Nygaard; Hansen, Finn; Willén, Dag

    2001-01-01

    In order to operate a superconducting cable conductor it must be kept at a cryogenic temperature (e.g. using liquid nitrogen). The superconducting cable conductor is at high voltage and the cooling equipment is kept at ground potential. This requires a thermally insulating connection that is also...... strength. However, samples of ExpancelÒ (polymer foam) have recently proved to withstand large electrical fields at room temperature as well as at cryogenic temperatures. In this work, two prototype devices have been tested with respect to the partial discharge inception voltage, thermal insulation...

  20. 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).