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Sample records for dual mode inverter

  1. Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede

    2007-01-01

    This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck......-boost power conversion to be performed over a wide modulation range, with three-level output waveforms generated. The connection of an additional transformer to the inverter ac output also allows all generic wye-or delta-connected loads with three-wire or four-wire configuration to be supplied by the inverter....... Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays...

  2. Thermal Equilibrium Dynamic Control Based on DPWM Dual-Mode Modulation of High Power NPC Three-Level Inverter

    Directory of Open Access Journals (Sweden)

    Shi-Zhou Xu

    2016-01-01

    Full Text Available In some special applications of NPC three-level inverters, such as mine hoist, there exist special conditions of overloading during the whole hoisting process and large overload in starting stage, during which the power-loss calculation of power devices and thermal control are important factors affecting the thermal stability of inverters. The principles of SVPWM and DPWM were described in this paper firstly, based on which the dynamic power losses of the two modulations of hoist in single period were calculated. Secondly, a thermal equilibrium dynamic control based on DPMW dual-mode modulation was proposed, which can switch the modulation dynamically according to the change of dynamic power loss to realize dynamic control of power loss and thermal equilibrium of inverter. Finally, simulation and experiment prove the effectiveness of the proposed strategy.

  3. Extending the Constant Power Speed Range of the Brushless DC Motor through Dual Mode Inverter Control -- Part I: Theory and Simulation

    International Nuclear Information System (INIS)

    Lawler, J.S.

    2001-01-01

    An inverter topology and control scheme has been developed that can drive low-inductance, surface-mounted permanent magnet motors over the wide constant power speed range required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC)[1]. The DMIC can drive either the Permanent Magnet Synchronous Machine (PMSM) with sinusoidal back emf, or the brushless dc machine (BDCM) with trapezoidal emf in the motoring and regenerative braking modes. In this paper we concentrate on the BDCM under high-speed motoring conditions. Simulation results show that if all motor and inverter loss mechanisms are neglected, the constant power speed range of the DMIC is infinite. The simulation results are supported by closed form expressions for peak and rms motor current and average power derived from analytical solution to the differential equations governing the DMIC/BDCM drive for the lossless case. The analytical solution shows that the range of motor inductance that can be accommodated by the DMIC is more than an order of magnitude such that the DMIC is compatible with both low- and high-inductance BDCMs. Finally, method is given for integrating the classical hysteresis band current control, used for motor control below base speed, with the phase advance of DMIC that is applied above base speed. The power versus speed performance of the DMIC is then simulated across the entire speed range

  4. Thermal Equilibrium Dynamic Control Based on DPWM Dual-Mode Modulation of High Power NPC Three-Level Inverter

    OpenAIRE

    Xu, Shi-Zhou; He, Feng-You

    2016-01-01

    In some special applications of NPC three-level inverters, such as mine hoist, there exist special conditions of overloading during the whole hoisting process and large overload in starting stage, during which the power-loss calculation of power devices and thermal control are important factors affecting the thermal stability of inverters. The principles of SVPWM and DPWM were described in this paper firstly, based on which the dynamic power losses of the two modulations of hoist in single pe...

  5. Extending the Constant Power Speed Range of the Brushless DC Motor through Dual Mode Inverter Control - Part II: Laboratory Proof-of-Principle

    International Nuclear Information System (INIS)

    Lawler, J.S.

    2001-01-01

    Previous theoretical work has shown that when all loss mechanisms are neglected the constant power speed range (CPSR) of a brushless dc motor (BDCM) is infinite when the motor is driven by the dual-mode inverter control (DMIC)[1,2]. In a physical drive, losses, particularly speed-sensitive losses, will limit the CPSR to a finite value. In this paper we report the results of laboratory testing of a low-inductance, 7.5-hp BDCM driven by the DMIC. The speed rating of the test motor rotor limited the upper speed of the testing, and the results show that the CPSR of the test machine is greater than 6:1 when driven by the DMIC. Current wave shape, peak, and rms values remained controlled and within rating over the entire speed range. The laboratory measurements allowed the speed-sensitive losses to be quantified and incorporated into computer simulation models, which then accurately reproduce the results of lab testing. The simulator shows that the limiting CPSR of the test motor is 8:1. These results confirm that the DMIC is capable of driving low-inductance BDCMs over the wide CPSR that would be required in electric vehicle applications

  6. Dual-Mode Combustor

    Science.gov (United States)

    Trefny, Charles J (Inventor); Dippold, Vance F (Inventor)

    2013-01-01

    A new dual-mode ramjet combustor used for operation over a wide flight Mach number range is described. Subsonic combustion mode is usable to lower flight Mach numbers than current dual-mode scramjets. High speed mode is characterized by supersonic combustion in a free-jet that traverses the subsonic combustion chamber to a variable nozzle throat. Although a variable combustor exit aperture is required, the need for fuel staging to accommodate the combustion process is eliminated. Local heating from shock-boundary-layer interactions on combustor walls is also eliminated.

  7. Research on Control Strategies of an Open-End Winding Permanent Magnet Synchronous Driving Motor (OW-PMSM-Equipped Dual Inverter with a Switchable Winding Mode for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Liang Chu

    2017-05-01

    Full Text Available An open-end winding permanent magnet synchronous motor (PMSM has a larger range of speed regulation than normal PMSM with the same DC voltage, and the control method is more flexible. It can also manage energy distribution between two power sources without a DC/DC converter. This paper aims at an electric vehicle equipped with OW-PMSM drive system with dual power sources and dual inverters; based on analyzing the external characteristics of each winding mode, we propose a winding mode switching strategy whose torque saturation judgmental algorithm, which is insensitive to motor’s parameters, could automatically realize upswitching of the winding mode. The proposed multi-level current hysteresis modulation algorithm could set the major power source and switch it at any time in independent mode, which accomplishes energy distribution between two power sources; its two control methods, low switching frequency method and high power difference method, could achieve different energy distribution effects. Simulation results confirm the validity and effectiveness of the winding mode switching strategy and current modulation method. They also show that an electric vehicle under the proposed control methods has better efficiency than one equipped with a traditional OW-PMSM drive system under traditional control.

  8. Dual voltage source inverter topology extending machine operating range

    NARCIS (Netherlands)

    Gerrits, T.; Wijnands, C.G.E.; Paulides, J.J.H.; Duarte, J.L.

    2012-01-01

    Field weakening operation of an electrical machine is a conventional method to extend the angular velocity range of a system above the peak output voltage of the inverter. A downside, however, is that an increased reactive current is required that creates losses but no output torque. A dual voltage

  9. Model predictive control for a dual active bridge inverter with a floating bridge

    OpenAIRE

    Chowdhury, Shajjad; Wheeler, Patrick W.; Gerada, C.; Patel, Chintan

    2016-01-01

    This paper presents a Model Predictive Control technique applied to a dual active bridge inverter where one of the bridges is floating. The proposed floating bridge topology eliminates the need for isolation transformer in a dual inverter system and therefore reduces the size, weight and losses in the system. To achieve multilevel output voltage waveforms the floating inverter DC link capacitor is charged to the half of the main DC link voltage. A finite-set Model Predictive Control technique...

  10. An extended dual input dual output three level Z source inverter with improved switch loss reduction technique

    Directory of Open Access Journals (Sweden)

    N.B. Deshmukh

    2016-12-01

    Full Text Available Multilevel inverter (MLI is a proven technology used for industrial applications due to low output total harmonic distortion (THD, high power handling capability and low active device rating. Dual output inverter is a recent trend associated with inverter topologies for specialized applications. This paper deals with three phase three level dual input dual output inverter topology with minimum active device count. Reduction in switch count leads to reduction in losses and improves reliability. Both the input sources share power equally as neutral point current ripple is maintained low. For further reduction in switching losses at higher switching frequencies, the concept of “no switching zone” or discontinuous pulse width modulation (DPWM has been put forth recently. This paper proposes modification in the placement of “no switching zone” in order to optimize switching losses and output THD (output filtering requirements for low power factor load. This study also proposes novel graphical approach to analyze the loss reduction along with its effect on output THD. The sinusoidal PWM (SPWM is used which gives satisfactory switching loss reduction without complex calculations. Moreover, the proposed topology is generalized to provide dual output at higher voltage levels. It is seen that the components reduction phenomenon becomes more pronounced as number of levels goes on increasing. The proposed converter is simulated in MATLAB software environment and results are obtained.

  11. Mode tunable p-type Si nanowire transistor based zero drive load logic inverter.

    Science.gov (United States)

    Moon, Kyeong-Ju; Lee, Tae-Il; Lee, Sang-Hoon; Han, Young-Uk; Ham, Moon-Ho; Myoung, Jae-Min

    2012-07-25

    A design platform for a zero drive load logic inverter consisting of p-channel Si nanowire based transistors, which controlled their operating mode through an implantation into a gate dielectric layer was demonstrated. As a result, a nanowire based class D inverter having a 4.6 gain value at V(DD) of -20 V was successfully fabricated on a substrate.

  12. New Switched-Dual-Source Multilevel Inverter for Symmetrical and Asymmetrical Operation

    Directory of Open Access Journals (Sweden)

    Kennedy Adinbo Aganah

    2018-04-01

    Full Text Available The increasing integration of large solar PV and wind farms into the power grid has fueled, over the past two decades, growing demands for high-power, high-voltage, utility-scale inverters. Multilevel inverters have emerged as the industry’s choice for megawatt-range inverters because of their reduced voltage stress, capability for generating an almost-sinusoidal voltage, built-in redundancy and other benefits. This paper presents a novel switched-source multilevel inverter (SS MLI architecture. This new inverter shows superior capabilities when compared to existing topologies. It has reduced voltage stress on the semiconductor, uses fewer switches (i.e., reduced size/weight/cost and exhibits increased efficiency. The proposed SS MLI is comprised of two voltage sources ( V 1 , V 2 and six switches. It is capable of generating five-level output voltage in symmetric mode (i.e., V 1 = V 2 and seven-level output voltage in asymmetric mode (i.e., V 1 ≠ V 2 . We present simulations results (using MATLAB®/Simulink® for five- and seven-level output voltages, and they strongly support the validity of the proposed inverter. These positive results are further supported experimentally using a laboratory prototype.

  13. Modified Dual Three-Pulse Modulation technique for single-phase inverter topology

    Science.gov (United States)

    Sree Harsha, N. R.; Anitha, G. S.; Sreedevi, A.

    2016-01-01

    In a recent paper, a new modulation technique called Dual Three Pulse Modulation (DTPM) was proposed to improve the efficiency of the power converters of the Electric/Hybrid/Fuel-cell vehicles. It was simulated in PSIM 9.0.4 and uses analog multiplexers to generate the modulating signals for the DC/DC converter and inverter. The circuit used is complex and many other simulation softwares do not support the analog multiplexers as well. Also, the DTPM technique produces modulating signals for the converter, which are essentially needed to produce the modulating signals for the inverter. Hence, it cannot be used efficiently to switch the valves of a stand-alone inverter. We propose a new method to generate the modulating signals to switch MOSFETs of a single phase Dual-Three pulse Modulation based stand-alone inverter. The circuits proposed are simulated in Multisim 12.0. We also show an alternate way to switch a DC/DC converter in a way depicted by DTPM technique both in simulation (MATLAB/Simulink) and hardware. The circuitry is relatively simple and can be used for the further investigations of DTPM technique.

  14. Interference of Spin-2 Self-Dual Modes

    OpenAIRE

    Ilha, Anderson; Wotzasek, Clovis

    2001-01-01

    We study the effects of interference between the self-dual and anti self-dual massive modes of the linearized Einstein-Chern-Simons topological gravity. The dual models to be used in the interference process are carefully analyzed with special emphasis on their propagating spectrum. We identify the opposite dual aspects, necessary for the application of the interference formalism on this model. The soldered theory so obtained displays explicitly massive modes of the Proca type. It may also be...

  15. Optimized Carrier Based Multilevel Generated Modified Dual Three-Phase Open-Winding Inverter for Medium Power Applications

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick

    2016-01-01

    This paper presents a novel carrier based multilevel modulation for modified dual three-phase open-winding inverter applicable for low-voltage/high-current applications. A standard three-phase voltage source inverter (VSI) is connected across the open-winding of both ends of the motor. Each VSI i...

  16. Automotive dual-mode hydrogen generation system

    Science.gov (United States)

    Kelly, D. A.

    The automotive dual mode hydrogen generation system is advocated as a supplementary hydrogen fuel means along with the current metallic hydride hydrogen storage method for vehicles. This system consists of utilizing conventional electrolysis cells with the low voltage dc electrical power supplied by two electrical generating sources within the vehicle. Since the automobile engine exhaust manifold(s) are presently an untapped useful source of thermal energy, they can be employed as the heat source for a simple heat engine/generator arrangement. The second, and minor electrical generating means consists of multiple, miniature air disk generators which are mounted directly under the vehicle's hood and at other convenient locations within the engine compartment. The air disk generators are revolved at a speed which is proportionate to the vehicles forward speed and do not impose a drag on the vehicles motion.

  17. Synchronised PWM Schemes for Three-level Inverters with Zero Common-mode Voltage

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede

    2002-01-01

    This paper presents results of analysis and comparison of novel synchronised schemes of pulsewidth modulation (PWM), applied to three-level voltage source inverters with control algorithms providing elimination of the common-mode voltage. The proposed approach is based on a new strategy of digital...

  18. Comparison of Output Current Ripple in Single and Dual Three-Phase Inverters for Electric Vehicle Motor Drives

    Directory of Open Access Journals (Sweden)

    Jelena Loncarski

    2015-04-01

    Full Text Available The standard solution for the traction system in battery powered electric vehicles (EVs is a two-level (2L inverter feeding a three-phase motor. A simple and effective way to achieve a three-level (3L inverter in battery-supplied electric vehicles consists of using two standard three-phase 2L inverters with the open-end winding connection of standard three-phase ac motors. The 3L inverter solution can be usefully adopted in EVs since it combines several benefits such as current ripple reduction, increment of phase motor voltage with limited voltage ratings of the two battery banks, improvement in system reliability, etc. The reduction in current ripple amplitude is particularly relevant since it is a source of electromagnetic interference and audio noise from the inverter-motor power connection cables and from the motor itself. By increasing the inverter switching frequency the ripple amplitude is reduced, but the drive efficiency decreases due to the proportionally increased switching losses. In this paper the peak-to-peak ripple amplitude of the dual-2L inverter is evaluated and compared with the corresponding ripple of the single-2L inverter, considering the same voltage and power motor ratings. The ripple analysis is carried out as a function of the modulation index to cover the whole modulation range of the inverter, and the theoretical results are verified with experimental tests carried out by an inverter-motor drive prototype.

  19. Dual-cavity mode converter for a fundamental mode output in an over-moded relativistic backward-wave oscillator

    International Nuclear Information System (INIS)

    Li, Jiawei; Huang, Wenhua; Xiao, Renzhen; Bai, Xianchen; Zhang, Yuchuan; Zhang, Xiaowei; Shao, Hao; Chen, Changhua; Zhu, Qi

    2015-01-01

    A dual-cavity TM 02 –TM 01 mode converter is designed for a dual-mode operation over-moded relativistic backward-wave oscillator. With the converter, the fundamental mode output is achieved. Particle-in-cell simulation shows that the efficiency of beam-wave conversion was over 46% and a pureTM 01 mode output was obtained. Effects of end reflection provided by the mode converter were studied. Adequate TM 01 mode feedback provided by the converter enhances conversion efficiency. The distance between the mode converter and extraction cavity critically affect the generation of microwaves depending on the reflection phase of TM 01 mode feedback

  20. Properties of ion temperature gradient and trapped electron modes in tokamak plasmas with inverted density profiles

    Science.gov (United States)

    Du, Huarong; Jhang, Hogun; Hahm, T. S.; Dong, J. Q.; Wang, Z. X.

    2017-12-01

    We perform a numerical study of linear stability of the ion temperature gradient (ITG) mode and the trapped electron mode (TEM) in tokamak plasmas with inverted density profiles. A local gyrokinetic integral equation is applied for this study. From comprehensive parametric scans, we obtain stability diagrams for ITG modes and TEMs in terms of density and temperature gradient scale lengths. The results show that, for the inverted density profile, there exists a normalized threshold temperature gradient above which the ITG mode and the TEM are either separately or simultaneously unstable. The instability threshold of the TEM for the inverted density profile is substantially different from that for normal and flat density profiles. In addition, deviations are found on the ITG threshold from an early analytic theory in sheared slab geometry with the adiabatic electron response [T. S. Hahm and W. M. Tang, Phys. Fluids B 1, 1185 (1989)]. A possible implication of this work on particle transport in pellet fueled tokamak plasmas is discussed.

  1. Common mode voltage in case of transformerless PV inverters connected to the grid

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Teodorescu, Remus; Liserre, Marco

    2008-01-01

    For safety reasons grid connected PV systems include galvanic isolation. In case of transformerless inverters, the leakage ground current through the parasitic capacitance of the PV panels, can reach very high values. A common-mode model based on analytical approach is introduced, used to predict...... the common-mode behavior, at frequencies lower than 50kHz, of the selected topologies and to explain the influence of system imbalance on the leakage current. It will be demonstrated that the neutral inductance has a crucial influence on the leakage current. Finally experimental results will be shown...

  2. Dual-Mode Scramjet Flameholding Operability Measurements

    Science.gov (United States)

    Donohue, James M.

    2012-01-01

    Flameholding measurements were made in two different direct connect combustor facilities that were designed to simulate a cavity flameholder in the flowfield of a hydrocarbon fueled dual-mode scramjet combustor. The presence of a shocktrain upstream of the flameholder has a significant impact on the inlet flow to the combustor and on the flameholding limits. A throttle was installed in the downstream end of the test rigs to provide the needed back-pressurization and decouple the operation of the flameholder from the backpressure formed by heat release and thermal choking, as in a flight engine. Measurements were made primarily with ethylene fuel but a limited number of tests were also performed with heated gaseous JP-7 fuel injection. The flameholding limits were measured by ramping inlet air temperature down until blowout was observed. The tests performed in the United Technologies Research Center (UTRC) facility used a hydrogen fueled vitiated air heater, Mach 2.2 and 3.3 inlet nozzles, a scramjet combustor rig with a 1.666 by 6 inch inlet and a 0.65 inch deep cavity. Mean blowout temperature measured at the baseline condition with ethylene fuel, the Mach 2.2 inlet and a cavity pressure of 21 psia was 1502 oR. Flameholding sensitivity to a variety of parameters was assessed. Blowout temperature was found to be most sensitive to fuel injection location and fuel flowrates and surprisingly insensitive to operating pressure (by varying both back-pressurization and inlet flowrate) and inlet Mach number. Video imaging through both the bottom and side wall windows was collected simultaneously and showed that the flame structure was quite unsteady with significant lateral movements as well as movement upstream of the flameholder. Experiments in the University of Virginia (UVa) test facility used a Mach 2 inlet nozzle with a 1 inch by 1.5 inch exit cross section, an aspect ratio of 1.5 versus 3.6 in the UTRC facility. The UVa facility tests were designed to measure the

  3. A Double Inverted F-Shape Patch Antenna for Dual-Band Operation

    Directory of Open Access Journals (Sweden)

    M. M. Islam

    2014-01-01

    Full Text Available A double inverted F-shape patch antenna is presented for dual-band operation. The proposed antenna is comprised of circular and rectangular slots on a printed circuit board of 40 mm × 40 mm × 1.6 mm with a 50 Ω microstrip transmission line. Commercially available high frequency structural simulator (HFSS based on the finite element method (FEM has been adopted in this investigation. It has a measured impedance bandwidths (2 : 1 VSWR of 18.53% on the lower band and 7.8% on the upper band, respectively. It has achieved stable radiation efficiencies of 79.76% and 80.36% with average gains of 7.82 dBi and 5.66 dBi in the operating frequency bands. Moreover, numerical simulations have been indicated as an important uniformity with measured results.

  4. A Balanced-Fed Dual Inverted-F Antenna with Reduced Human Body Effects

    Directory of Open Access Journals (Sweden)

    Wang-Sang Lee

    2013-01-01

    Full Text Available A balanced-fed dual inverted-F antenna with reduced human body effects for WLAN applications at 2.45 GHz is presented. In order to reduce the influence by a close proximity or a touch of a human body, the proposed antenna employs an impedance matching using a lumped LC-balun which has the simple and compact structure applying for mobile handsets. The resonant frequency of the proposed antenna is fixed at 2.45 GHz regardless of the close proximity of a human body. By applying for the L-shape ground plane, the proposed antenna has the wide impedance bandwidth of about 150 MHz and the peak realized gain of about 4 dBi.

  5. Financial Management of Distance Learning in Dual-Mode Institutions

    Science.gov (United States)

    Rumble, Greville

    2012-01-01

    Dual-mode universities operating in a tough economic environment need to be able to answer a range of questions concerning their use of different teaching modes accurately and with confidence. Only an activity-based costing approach will provide them with this tool. Cost studies of other distance learning projects may provide benchmarks against…

  6. Tapping mode imaging and measurements with an inverted atomic force microscope.

    Science.gov (United States)

    Chan, Sandra S F; Green, John-Bruce D

    2006-07-18

    This report demonstrates the successful use of the inverted atomic force microscope (i-AFM) for tapping mode AFM imaging of cantilever-supported samples. i-AFM is a mode of AFM operation in which a sample supported on a tipless cantilever is imaged by one of many tips in a microfabricated tip array. Tapping mode is an intermittent contact mode whereby the cantilever is oscillated at or near its resonance frequency, and the amplitude and/or phase are used to image the sample. In the process of demonstrating that tapping mode images could be obtained in the i-AFM design, it was observed that the amplitude of the cantilever oscillation decreased markedly as the cantilever and tip array were approached. The source of this damping of the cantilever oscillations was identified to be the well-known "squeeze film damping", and the extent of damping was a direct consequence of the relatively shorter tip heights for the tip arrays, as compared to those of commercially available tapping mode cantilevers with integrated tips. The functional form for the distance dependence of the damping coefficient is in excellent agreement with previously published models for squeeze film damping, and the values for the fitting parameters make physical sense. Although the severe damping reduces the cantilever free amplitude substantially, we found that we were still able to access the low-amplitude regime of oscillation necessary for attractive tapping mode imaging of fragile molecules.

  7. Dual Band Planar Inverted F Antenna (PIFA with L-Shape Configuration

    Directory of Open Access Journals (Sweden)

    khlouf Munzer Mohamad

    2017-01-01

    Full Text Available One of the most used antennas in mobile devices is planar inverted F antenna (PIFA. PIFA can be design in dual band frequencies due to the coverage of the wireless service in a mobile device that requires a multiple frequencies. However, the consideration of technical operation has to be combined with an evaluation of the antenna radiation impact on the users. A procedure of PIFA work in GSM (867-960MHz and GSM (1710-1899MHz is done using CST Software. The dual band frequency response is obtained by means of an insertion of an L-shaped slot, which is use to tune the operation frequencies. The prototype of the antenna is fabricated as model by CST Software and evaluated. It is found out that the PIFA antenna has a good efficiency, bandwidth as well as produce a maximum gain for the antenna. A key and innovative research is still underway to broaden performance parameters of the antenna.

  8. Diamond logic inverter with enhancement-mode metal-insulator-semiconductor field effect transistor

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J. W., E-mail: liu.jiangwei@nims.go.jp [International Center for Young Scientists (ICYS), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Liao, M. Y.; Imura, M. [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Watanabe, E.; Oosato, H. [Nanofabrication Platform, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Koide, Y., E-mail: koide.yasuo@nims.go.jp [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Nanofabrication Platform, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Center of Materials Research for Low Carbon Emission, NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2014-08-25

    A diamond logic inverter is demonstrated using an enhancement-mode hydrogenated-diamond metal-insulator-semiconductor field effect transistor (MISFET) coupled with a load resistor. The gate insulator has a bilayer structure of a sputtering-deposited LaAlO{sub 3} layer and a thin atomic-layer-deposited Al{sub 2}O{sub 3} buffer layer. The source-drain current maximum, extrinsic transconductance, and threshold voltage of the MISFET are measured to be −40.7 mA·mm{sup −1}, 13.2 ± 0.1 mS·mm{sup −1}, and −3.1 ± 0.1 V, respectively. The logic inverters show distinct inversion (NOT-gate) characteristics for input voltages ranging from 4.0 to −10.0 V. With increasing the load resistance, the gain of the logic inverter increases from 5.6 to as large as 19.4. The pulse response against the high and low input voltages shows the inversion response with the low and high output voltages.

  9. Dual-cavity mode converter for a fundamental mode output in an over-moded relativistic backward-wave oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jiawei; Huang, Wenhua [Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230027 (China); Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Xiao, Renzhen; Bai, Xianchen; Zhang, Yuchuan; Zhang, Xiaowei; Shao, Hao; Chen, Changhua [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Zhu, Qi [Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230027 (China)

    2015-03-16

    A dual-cavity TM{sub 02}–TM{sub 01} mode converter is designed for a dual-mode operation over-moded relativistic backward-wave oscillator. With the converter, the fundamental mode output is achieved. Particle-in-cell simulation shows that the efficiency of beam-wave conversion was over 46% and a pureTM{sub 01} mode output was obtained. Effects of end reflection provided by the mode converter were studied. Adequate TM{sub 01} mode feedback provided by the converter enhances conversion efficiency. The distance between the mode converter and extraction cavity critically affect the generation of microwaves depending on the reflection phase of TM{sub 01} mode feedback.

  10. A Riding-through Technique for Seamless Transition between Islanded and Grid-Connected Modes of Droop-Controlled Inverters

    DEFF Research Database (Denmark)

    Hu, Shang-hung; Lee, Tzung-Lin; Kuo, Chun-Yi

    2016-01-01

    This paper presents a seamless transition method for a droop-controlled inverter. The droop control is suitable to make the inverter work as a voltage source in both islanded and grid-connected modes, however, the transfer between theses modes can result in a big inrush current that may damage...... a smooth transition between them, requiring neither synchronization signals nor grid-side information. The control algorithm and design procedure are presented. Experimental results from a laboratory prototype validate the effectiveness of the proposed method....... the system. The proposed method allows the droop-controlled inverter to improve the transient response when transferring between modes, by detecting the inrush current, activating a current control loop during transients, and then transferring back to droop-controlled mode smoothly by using a virtual...

  11. Research tokamak system with multi-mode discharges using inverter power supply

    International Nuclear Information System (INIS)

    Kojima, Hiroki; Kobayashi, Masahiro; Takagi, Makoto; Takamura, Shuichi; Tashiro, Kenji

    1999-01-01

    In Current Sustaining Tokamak in Nagoya university (CSTN)-IV research tokamak system using a compact 40kHz pulse width modulation (PWM) inverter power supply, which is controlled through LabVIEW program, we construct a new tokamak discharge system with multi-mode including a stable alternating current discharge and a high-repetition high-duty one. These discharge modes can be operated continuously for as long as 60sec. The continuous discharge with long duration is able to simulate the important physical and chemical processes of long time discharges in fusion devices, in which the heat load to the wall and the particle balance in the plasma-wall system are crucial topics in order to realize a long pulse fusion reactor, like ITER. Employing ergodic divertor (ED) is one of tools to control the particle balance and the heat load to the wall. In addition, we installed another inverter power supply to generate a rotating magnetic perturbation for dynamic ergodic divertor (DED) with the appropriate measurement system so that we may carry out experiments on heat and particle control with DED at long time operation. (author)

  12. The Strategy of Inverter Seamless Mode Switching in Master-Slave Independent Micro-grid

    Directory of Open Access Journals (Sweden)

    Jiang Hanhong

    2018-01-01

    Full Text Available In order to realize the uninterruptible power supply in the master-slave independent micro-grid system, the micro-grid inverter needs to realize the mode switching of the grid-connection/grid-disconnection. How to reduce the transient oscillation during switching, so as to effectively achieve seamless mode switching is a key issue to be solved. In this paper, a typical master-slave control independent micro-grid is used as an example, the strategy of mode switching is improved in two aspects. On the one hand, the state-following algorithm is adopted to improve the switching strategy of the outer loop. On the other hand, the current inner loop is taken by the H∞ robust controller to improve the robustness of the controller. Compared with the traditional PI control mode switching, this paper illustrates the feasibility of the proposed strategy through the simulation and experiment verification. The improvement strategy in this paper can effectively reduce the voltage and current oscillation during mode switching.

  13. Examining Policy Guidelines for Distance Education in Dual Mode ...

    African Journals Online (AJOL)

    The study reports a case of distance education policy in the Kwame Nkrumah University of Science and Technology (KNUST), a dual mode University in Ghana. The interview method was used to obtain information from 21 purposively selected key informants in the University. Policy documents that addressed Distance ...

  14. Dual-view inverted selective plane illumination microscopy (diSPIM) with improved background rejection for accurate 3D digital pathology

    Science.gov (United States)

    Hu, Bihe; Bolus, Daniel; Brown, J. Quincy

    2018-02-01

    Current gold-standard histopathology for cancerous biopsies is destructive, time consuming, and limited to 2D slices, which do not faithfully represent true 3D tumor micro-morphology. Light sheet microscopy has emerged as a powerful tool for 3D imaging of cancer biospecimens. Here, we utilize the versatile dual-view inverted selective plane illumination microscopy (diSPIM) to render digital histological images of cancer biopsies. Dual-view architecture enabled more isotropic resolution in X, Y, and Z; and different imaging modes, such as adding electronic confocal slit detection (eCSD) or structured illumination (SI), can be used to improve degraded image quality caused by background signal of large, scattering samples. To obtain traditional H&E-like images, we used DRAQ5 and eosin (D&E) staining, with 488nm and 647nm laser illumination, and multi-band filter sets. Here, phantom beads and a D&E stained buccal cell sample have been used to verify our dual-view method. We also show that via dual view imaging and deconvolution, more isotropic resolution has been achieved for optical cleared human prostate sample, providing more accurate quantitation of 3D tumor architecture than was possible with single-view SPIM methods. We demonstrate that the optimized diSPIM delivers more precise analysis of 3D cancer microarchitecture in human prostate biopsy than simpler light sheet microscopy arrangements.

  15. COMPACT DUAL-BAND INVERTED L SHAPED MONOPOLE ANTENNA FOR WLAN APPLICATIONS

    Directory of Open Access Journals (Sweden)

    K Sumathi

    2015-12-01

    Full Text Available A highly compact and an optimized design of an Inverted L shaped printed monopole antenna with a simple compact ground plane is proposed. To make the designed antenna suitable for implantation it is embedded in FR-4 substrate and is presented. The antenna is designed for dual-band operation at 2.4GHz and 5.2GHz. It is suitable for Wireless Local Area Network (WLAN applications with return loss (S11 < -10dB. The antenna has two different resonant current paths that support two resonances at 2.44GHz and 5.18GHz (forming an F-shaped structure. The size of the antenna is 32.5mm × 19.6mm × 1.6mm. The antenna design is simulated using the tool Advanced Design System (ADS 2014. This antenna design has good return loss and radiation characteristics in both the required frequency bands. The radiation pattern obtained from the proposed antenna is an Omni directional radiation pattern in the E and H plane over the frequency ranges 2.4GHz and 5.2GHz.

  16. High performance fuzzy sliding mode control of DFIG supplied by seven level NPC inverter

    Directory of Open Access Journals (Sweden)

    Mohamed BENKAHLA

    2017-09-01

    Full Text Available This article presents the powers control of a variable speed wind turbine (WT based on a doubly fed induction generator (DFIG because of their advantages in terms of economy and control. The considered system consists of a double fed induction generator whose stator is connected directly to the network and its rotor is supplied by seven-level inverter with structure NPC are well used to minimize the harmonics absorbed by the DFIG. In order to control the power flowing between the stator of the DFIG and the grid. Have been studied and compared two types of controllers : Sliding Mode Control (SMC and Fuzzy SMC (FSMC. Their respective performances are compared in terms of power reference tracking, response to sudden speed variations, sensitivity to perturbations and robustness against machine parameters variations.

  17. Three-Level Inverters with Common-Mode Voltage Cancellation Based on Synchronous Pulsewidth Modulation

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede

    2002-01-01

    A novel method of direct synchronous pulse-width modulation (PWM) is disseminated to three-level voltage source inverters with control algorithms with elimination of the common-mode voltages in three-phase drive systems with PWM. It provides smooth pulses-ratio changing and a quarter-wave symmetry...... of the voltage waveforms during the whole control range including overmodulation. Continuous, discontinuous and "direct-direct" schemes of synchronous PWM with both algebraic and trigonometric control functions have been analysed and compared. Simulations give the behaviour of the proposed methods and show some...... advantages of synchronous PWM in comparison with asynchronous at low ratios between the switching frequency and fundamental frequency....

  18. Synchronised Voltage Space Vector Modulation for Three-level Inverters with Common-mode Voltage Elimination

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede

    2002-01-01

    A novel method of direct synchronous pulse-width modulation (PWM) is disseminated to three-level voltage source inverters with control algorithms with elimination of the common-mode voltages in three-phase drive systems with PWM. It provides smooth pulses-ratio changing and a quarter-wave symmetry...... of the voltage waveforms during the whole control range including overmodulation. Continuous, discontinuous and "direct-direct" schemes of synchronous PWM with both algebraic and trigonometric control functions have been analysed and compared. Simulations give the behaviour of the proposed methods and show some...... advantages of synchronous PWM in comparison with asynchronous at low ratios between the switching frequency and fundamental frequency....

  19. Development and Use of the Dual-Mode Plasma Torch

    International Nuclear Information System (INIS)

    Womack, R.; Shuey, M.

    2002-01-01

    After several years of development, a commercially available high-temperature treatment system has been developed and installed that treats heterogeneous low-level radioactive waste. High temperature plasma processing, unique torch design and operating features make it feasible to achieve a volume reduced, permanent, high integrity waste form while eliminating the personnel exposure and costs associated with conventional sorting, characterizing and handling. Plasma technology can also be used to treat previous conditioned waste packages that no longer meet the current acceptance criteria for final disposal. Plasma treatment can result, in many cases, in a substantial volume reduction, which lowers the final disposal costs. This paper covers the recently patented dual mode plasma torch design(1), the lessons learned that fostered its development and the advantages it brings to radioactive waste processing. This paper also provides current full scale Plasma Arc Centrifugal Treatment (PACT) project status and how the dual mode torch is being used in the PACT system

  20. Adaptive Droop Control Applied to Voltage-Source Inverters Operating in Grid-Connected and Islanded Modes

    DEFF Research Database (Denmark)

    Vasquez, J. C.; Guerrero, J. M.; Luna, A.

    2009-01-01

    This paper proposes a novel control for voltagesource inverters with the capability to flexibly operate in gridconnected and islanded modes. The control scheme is based on the droop method, which uses some estimated grid parameters such as the voltage and frequency and the magnitude and angle of ...

  1. RTDS implementation of an improved sliding mode based inverter controller for PV system.

    Science.gov (United States)

    Islam, Gazi; Muyeen, S M; Al-Durra, Ahmed; Hasanien, Hany M

    2016-05-01

    This paper proposes a novel approach for testing dynamics and control aspects of a large scale photovoltaic (PV) system in real time along with resolving design hindrances of controller parameters using Real Time Digital Simulator (RTDS). In general, the harmonic profile of a fast controller has wide distribution due to the large bandwidth of the controller. The major contribution of this paper is that the proposed control strategy gives an improved voltage harmonic profile and distribute it more around the switching frequency along with fast transient response; filter design, thus, becomes easier. The implementation of a control strategy with high bandwidth in small time steps of Real Time Digital Simulator (RTDS) is not straight forward. This paper shows a good methodology for the practitioners to implement such control scheme in RTDS. As a part of the industrial process, the controller parameters are optimized using particle swarm optimization (PSO) technique to improve the low voltage ride through (LVRT) performance under network disturbance. The response surface methodology (RSM) is well adapted to build analytical models for recovery time (Rt), maximum percentage overshoot (MPOS), settling time (Ts), and steady state error (Ess) of the voltage profile immediate after inverter under disturbance. A systematic approach of controller parameter optimization is detailed. The transient performance of the PSO based optimization method applied to the proposed sliding mode controlled PV inverter is compared with the results from genetic algorithm (GA) based optimization technique. The reported real time implementation challenges and controller optimization procedure are applicable to other control applications in the field of renewable and distributed generation systems. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  2. Dual-mode optical microscope based on single-pixel imaging

    Science.gov (United States)

    Rodríguez, A. D.; Clemente, P.; Tajahuerce, E.; Lancis, J.

    2016-07-01

    We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no moving parts, works by sequential projection of a set of binary intensity patterns onto the sample that are codified onto a modified commercial DMD. Data to be displayed are geometrically transformed before written into a memory cell to cancel optical artifacts coming from the diamond-like shaped structure of the micromirror array. The 24-bit color depth of the display is fully exploited to increase the frame rate by a factor of 24, which makes the technique practicable for real samples. Our commercial DMD-based LED-illumination is cost effective and can be easily coupled as an add-on module for already existing inverted microscopes. The reflection and transmission information provided by our dual microscope complement each other and can be useful for imaging non-uniform samples and to prevent self-shadowing effects.

  3. Hardware Development of a Laboratory-Scale Microgrid Phase 1--Single Inverter in Island Mode Operation: Base Year Report, December 2000 -- November 2001

    Energy Technology Data Exchange (ETDEWEB)

    Venkataramanan, G.; Illindala, M. S.; Houle, C.; Lasseter, R. H.

    2002-11-01

    This report summarizes the activities of the first year of a three-year project to develop control software for micro-source distributed generation systems. The focus of this phase was on internal energy storage requirements, the modification of an off-the-shelf motor drive system inverter to supply utility-grade ac power, and a single inverter system operating in island mode. The report provides a methodology for determining battery energy storage requirements, a method for converting a motor drive inverter into a utility-grade inverter, and typical characteristics and test results of using such an inverter in a complex load environment.

  4. The performance test of a modified miniature rotary compressor in upright and inverted modes subjected to microgravity

    International Nuclear Information System (INIS)

    Ma, Rui; Wu, Yu-ting; Du, Chun-xu; Chen, Xia; Zhang, De-lou; Ma, Chong-fang

    2016-01-01

    Highlights: • A miniature rotary compressor by ASPEN company was modified. • The modified compressor can be employed in microgravity. • Performance of upright compressor is superior to inverted mode in most cases. • Performance curves of system with inverted compressor are obtained. • Experimental results of compressor inverted and upright are compared. - Abstract: Vapor compression heat pump is a new concept of thermal control system and refrigerator for future space use. Compressor is a key component in the vapor compression heat pump. Development of compressor capable of operating in both microgravity (10 E-6 g) and lunar (1/6 g) environments is urgently needed for space thermal control systems based on heat pump technique. In this paper, a miniature rotary compressor by ASPEN company was modified to realize acceptable compressor lubrication and oil circulation in microgravity environments. An experimental system was built up to check the performance of the modified compressor subjected to microgravity. A performances comparison of inverted compressor with upright one was made. The influences of operating parameters such as refrigerant charge, cooling water temperature as well as compressor speed on the performances of vapor compression heat pump were investigated. The results show that the modified miniature rotary compressor in inverted mode can operate stably in a long period, which indicates that the modified compressor can be employed in microgravity environments. Compressor discharge temperature increased or decreased while COP changed more obviously with cooling water temperature and speed in microgravity. In most cases, performance of the upright compressor is superior to that of the inverted one. But when the compressor speed is from 1500 rpm to 2500 rpm or the coolant temperature is between 20 and 25 degrees, the performance of inverted compressor is better. The highest discharge temperature of the inverted compressor can be as high

  5. A Dual-Mode Microwave Applicator for Liver Tumor Thermotherapy

    Science.gov (United States)

    Reimann, Carolin; Schüßler, Martin; Jakoby, Rolf; Bazrafshan, Babak; Hübner, Frank; Vogl, Thomas

    2018-03-01

    The concept of a novel dual-mode microwave applicator for diagnosis and thermal ablation treatment of tumorous tissue is presented in this paper. This approach is realized by integrating a planar resonator array to, firstly, detect abnormalities by a relative dielectric analysis, and secondly, perform a highly localized thermal ablation. A further essential advantage is addressed by designing the applicator to be MRI compatible to provide a multimodal imaging procedure. Investigations for an appropriate frequency range lead to the use of much higher operating frequencies between 5 GHz and 10 GHz, providing a significantly lower power consumption for microwave ablation of only 20 W compared to commercial available applicators.

  6. Volatile organic compounds discrimination based on dual mode detection

    Science.gov (United States)

    Yu, Yuanyuan; Wu, Enxiu; Chen, Yan; Feng, Zhihong; Zheng, Shijun; Zhang, Hao; Pang, Wei; Liu, Jing; Zhang, Daihua

    2018-06-01

    We report on a volatile organic compound (VOC) sensor that can provide concentration-independent signals toward target gases. The device is based on a dual-mode detection mechanism that can simultaneously record the mechanical (resonant frequency, f r) and electrical (current, I) responses of the same gas adsorption event. The two independent signals form a unique I–f r trace for each target VOC as the concentration varies. The mechanical response (frequency shift, Δf r) resulting from mass load on the device is directly related to the amount of surface adsorptions, while the electrical response (current variation, ΔI) is associated with charge transfer across the sensing interface and changes in carrier mobility. The two responses resulting from independent physical processes reflect intrinsic physical properties of each target gas. The ΔI–Δf r trace combined with the concentration dependent frequency (or current) signals can therefore be used to achieve target both recognition and quantification. The dual-mode device is designed and fabricated using standard complementary metal oxide semiconductor (CMOS) compatible processes. It exhibits consistent and stable performance in our tests with six different VOCs including ethanol, methanol, acetone, formaldehyde, benzene and hexane.

  7. EXPLAINING INVERTED-TEMPERATURE LOOPS IN THE QUIET SOLAR CORONA WITH MAGNETOHYDRODYNAMIC WAVE-MODE CONVERSION

    Energy Technology Data Exchange (ETDEWEB)

    Schiff, Avery J.; Cranmer, Steven R. [Department of Astrophysical and Planetary Sciences, Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309 (United States)

    2016-11-01

    Coronal loops trace out bipolar, arch-like magnetic fields above the Sun’s surface. Recent measurements that combine rotational tomography, extreme-ultraviolet imaging, and potential-field extrapolation have shown the existence of large loops with inverted-temperature profiles, i.e., loops for which the apex temperature is a local minimum, not a maximum. These “down loops” appear to exist primarily in equatorial quiet regions near solar minimum. We simulate both these and the more prevalent large-scale “up loops” by modeling coronal heating as a time-steady superposition of (1) dissipation of incompressible Alfvén wave turbulence and (2) dissipation of compressive waves formed by mode conversion from the initial population of Alfvén waves. We found that when a large percentage (>99%) of the Alfvén waves undergo this conversion, heating is greatly concentrated at the footpoints and stable “down loops” are created. In some cases we found loops with three maxima that are also gravitationally stable. Models that agree with the tomographic temperature data exhibit higher gas pressures for “down loops” than for “up loops,” which is consistent with observations. These models also show a narrow range of Alfvén wave amplitudes: 3 to 6 km s{sup -1} at the coronal base. This is low in comparison to typical observed amplitudes of 20–30 km s{sup -1} in bright X-ray loops. However, the large-scale loops we model are believed to compose a weaker diffuse background that fills much of the volume of the corona. By constraining the physics of loops that underlie quiescent streamers, we hope to better understand the formation of the slow solar wind.

  8. A novel dual mode neutron-gamma imager

    International Nuclear Information System (INIS)

    Cooper, Robert Lee; Gerling, Mark; Brennan, James S.; Mascarenhas, Nicholas; Mrowka, Stanley; Marleau, Peter

    2010-01-01

    The Neutron Scatter Camera (NSC) can image fission sources and determine their energy spectra at distances of tens of meters and through significant thicknesses of intervening materials in relatively short times (1). We recently completed a 32 element scatter camera and will present recent advances made with this instrument. A novel capability for the scatter camera is dual mode imaging. In normal neutron imaging mode we identify and image neutron events using pulse shape discrimination (PSD) and time of flight in liquid scintillator. Similarly gamma rays are identified from Compton scatter in the front and rear planes for our segmented detector. Rather than reject these events, we show it is possible to construct a gamma-ray image by running the analysis in a 'Compton mode'. Instead of calculating the scattering angle by the kinematics of elastic scatters as is appropriate for neutron events, it can be found by the kinematics of Compton scatters. Our scatter camera has not been optimized as a Compton gamma-ray imager but is found to work reasonably. We studied imaging performance using a Cs137 source. We find that we are able to image the gamma source with reasonable fidelity. We are able to determine gamma energy after some reasonable assumptions. We will detail the various algorithms we have developed for gamma image reconstruction. We will outline areas for improvement, include additional results and compare neutron and gamma mode imaging.

  9. Dual-Pump CARS Measurements in the University of Virginia's Dual-Mode Scramjet: Configuration "C"

    Science.gov (United States)

    Cutler, Andrew D.; Magnotti, Gaetano; Cantu, Luca; Gallo, Emanuela; Danehy, Paul M.; Rockwell, Robert; Goyne, Christopher; McDaniel, James

    2013-01-01

    Measurements have been conducted at the University of Virginia Supersonic Combustion Facility in configuration C of the dual-mode scramjet. This is a continuation of previously published works on configuration A. The scramjet is hydrogen fueled and operated at two equivalence ratios, one representative of the scram mode and the other of the ram mode. Dual-pump CARS was used to acquire the mole fractions of the major species as well as the rotational and vibrational temperatures of N2. Developments in methods and uncertainties in fitting CARS spectra for vibrational temperature are discussed. Mean quantities and the standard deviation of the turbulent fluctuations at multiple planes in the flow path are presented. In the scram case the combustion of fuel is completed before the end of the measurement domain, while for the ram case the measurement domain extends into the region where the flow is accelerating and combustion is almost completed. Higher vibrational than rotational temperature is observed in those parts of the hot combustion plume where there is substantial H2 (and hence chemical reaction) present.

  10. A dual-mode driver IC with monolithic negative drive-voltage capability and digital current-mode controller for depletion-mode GaN HEMT

    NARCIS (Netherlands)

    Wen, Y.; Rose, M.; Fernandes, R.; van Otten, R.; Bergveld, H.J.; Trescases, O.

    2017-01-01

    This work presents a driver and controller integrated circuit (IC) for depletion-mode gallium nitride (GaN) high-electron-mobility transistors (HEMTs). The dual-mode driver can be configured for cascode-drive (CD) or HEMT-drive (HD) mode. In the CD mode, a cascode low-voltage DMOS is driven to

  11. Silicon Integrated Dual-Mode Interferometer with Differential Outputs

    Directory of Open Access Journals (Sweden)

    Niklas Hoppe

    2017-09-01

    Full Text Available The dual-mode interferometer (DMI is an attractive alternative to Mach-Zehnder interferometers for sensor purposes, achieving sensitivities to refractive index changes close to state-of-the-art. Modern designs on silicon-on-insulator (SOI platforms offer thermally stable and compact devices with insertion losses of less than 1 dB and high extinction ratios. Compact arrays of multiple DMIs in parallel are easy to fabricate due to the simple structure of the DMI. In this work, the principle of operation of an integrated DMI with differential outputs is presented which allows the unambiguous phase shift detection with a single wavelength measurement, rather than using a wavelength sweep and evaluating the optical output power spectrum. Fluctuating optical input power or varying attenuation due to different analyte concentrations can be compensated by observing the sum of the optical powers at the differential outputs. DMIs with two differential single-mode outputs are fabricated in a 250 nm SOI platform, and corresponding measurements are shown to explain the principle of operation in detail. A comparison of DMIs with the conventional Mach-Zehnder interferometer using the same technology concludes this work.

  12. Modified Transformerless Dual Buck Inverter with Improved Lifetime for PV Applications

    DEFF Research Database (Denmark)

    Khan, Ahmad; Blaabjerg, Frede

    2018-01-01

    (CM) operation. The analyses are verified on a 3 kW system. The results indicated that a capacitor of 30 μF is adequate to achieve a ripple free DC-Bus voltage for a 3 kW inverter. The size of this capacitor is 50 times smaller compared to the original capacitor required by the system. Also, unlike...... the non-neutral point clamped topologies that eliminate the ground leakage current (e.g. HERIC and H5), the proposed system can attain grid-codes under non-unity power-factor and low solar irradiance level conditions....

  13. Towards model-based control of RCCI-CDF mode-switching in dual fuel engines

    NARCIS (Netherlands)

    Indrajuana, Armando; Bekdemir, C.; Feru, E.; Willems, F.P.T.

    2018-01-01

    The operation of a dual fuel combustion engine using combustion mode-switching offers the benefit of higher thermal efficiency compared to single-mode operation. For various fuel combinations, the engine research community has shown that running dual fuel engines in Reactivity Controlled Compression

  14. HIFU Monitoring and Control with Dual-Mode Ultrasound Arrays

    Science.gov (United States)

    Casper, Andrew Jacob

    The biological effects of high-intensity focused ultrasound (HIFU) have been known and studied for decades. HIFU has been shown capable of treating a wide variety of diseases and disorders. However, despite its demonstrated potential, HIFU has been slow to gain clinical acceptance. This is due, in part, to the difficulty associated with robustly monitoring and controlling the delivery of the HIFU energy. The non-invasive nature of the surgery makes the assessment of treatment progression difficult, leading to long treatment times and a significant risk of under treatment. This thesis research develops new techniques and systems for robustly monitoring HIFU therapies for the safe and efficacious delivery of the intended treatment. Systems and algorithms were developed for the two most common modes of HIFU delivery systems: single-element and phased array applicators. Delivering HIFU with a single element transducer is a widely used technique in HIFU therapies. The simplicity of a single element offers many benefits in terms of cost and overall system complexity. Typical monitoring schemes rely on an external device (e.g. diagnostic ultrasound or MRI) to assess the progression of therapy. The research presented in this thesis explores using the same element to both deliver and monitor the HIFU therapy. The use of a dual-mode ultrasound transducer (DMUT) required the development of an FPGA based single-channel arbitrary waveform generator and high-speed data acquisition unit. Data collected from initial uncontrolled ablations led to the development of monitoring and control algorithms which were implemented directly on the FPGA. Close integration between the data acquisition and arbitrary waveform units allowed for fast, low latency control over the ablation process. Results are presented that demonstrate control of HIFU therapies over a broad range of intensities and in multiple in vitro tissues. The second area of investigation expands the DMUT research to an

  15. Isolated/Non-Isolated Quad-Inverter Configuration for Multilevel Symmetrical/Asymmetrical Dual Six-Phase Star-Winding Converter

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Hontz, Michael R.; Khanna, Raghav

    2016-01-01

    This article presents the developments of a novel isolated/non-isolated quad inverter configuration for multilevel dual six-phase (twelve-phase) star-winding converter. The modular circuit consists of four standard voltage source inverters (VSIs). Each VSI is incorporated with one bi-directional ...... systems, electrical vehicles, AC tractions, and `More-Electric Aircraft' propulsion systems....... converter is numerically modeled using Matlab/PLECS simulation software and the predicted behavior of the system is analyzed and presented. Good agreement is obtained between these results and the theoretical analysis. Suitable applications for the converter include (low-voltage/high-current) medium power...

  16. Mode Adaptive Droop Control with Virtual Output Impedances for an Inverter-Based Flexible AC Microgrid

    DEFF Research Database (Denmark)

    Kim, Jaehong; Guerrero, Josep M.; Rodriguez, Pedro

    2011-01-01

    A decentralized power control method in a singlephase flexible acmicrogrid is proposed in this paper. Droop control is widely considered to be a good choice for managing the power flows between microgrid converters in a decentralized manner. In this work, to enhance the power loop dynamics, droop...... control combined with a derivative controller is used in islanded mode. In grid-connected mode, to strictly control the power factor in the point of common coupling (PCC), a droop method combined with an integral controller is adopted. Small-signal analysis of the proposed control is shown both...... in islanded and grid-connected mode. The proposed control scheme does not need any mode switching action. Thus, it is relatively simple in control for full mode of operation. Smooth transitions between the operation modes and the effectiveness of the proposed control scheme are evaluated through simulation...

  17. Analysis of balance control methods based on inverted pendulum for legged robots

    OpenAIRE

    Denisov, A.; Iakovlev, R.; Mamaev, I.; Pavliuk, N.

    2017-01-01

    Methods of balance control for a legged robot, the model of which is presented as a two-section inverted pendulum, are considered. The following balance methods for humanoid robots are analysed: the parallel algorithm of the network operator method; the method of natural synergies; the method of fuzzy control, the spherical inverted pendulum mode, a dual length linear inverted pendulum method. The best of these methods will be used in the development of the Russian anthropomorphic robot Antares.

  18. Analysis of balance control methods based on inverted pendulum for legged robots

    Directory of Open Access Journals (Sweden)

    Denisov Alexander

    2017-01-01

    Full Text Available Methods of balance control for a legged robot, the model of which is presented as a two-section inverted pendulum, are considered. The following balance methods for humanoid robots are analysed: the parallel algorithm of the network operator method; the method of natural synergies; the method of fuzzy control, the spherical inverted pendulum mode, a dual length linear inverted pendulum method. The best of these methods will be used in the development of the Russian anthropomorphic robot Antares.

  19. Adaptive lesion formation using dual mode ultrasound array system

    Science.gov (United States)

    Liu, Dalong; Casper, Andrew; Haritonova, Alyona; Ebbini, Emad S.

    2017-03-01

    We present the results from an ultrasound-guided focused ultrasound platform designed to perform real-time monitoring and control of lesion formation. Real-time signal processing of echogenicity changes during lesion formation allows for identification of signature events indicative of tissue damage. The detection of these events triggers the cessation or the reduction of the exposure (intensity and/or time) to prevent overexposure. A dual mode ultrasound array (DMUA) is used for forming single- and multiple-focus patterns in a variety of tissues. The DMUA approach allows for inherent registration between the therapeutic and imaging coordinate systems providing instantaneous, spatially-accurate feedback on lesion formation dynamics. The beamformed RF data has been shown to have high sensitivity and specificity to tissue changes during lesion formation, including in vivo. In particular, the beamformed echo data from the DMUA is very sensitive to cavitation activity in response to HIFU in a variety of modes, e.g. boiling cavitation. This form of feedback is characterized by sudden increase in echogenicity that could occur within milliseconds of the application of HIFU (see http://youtu.be/No2wh-ceTLs for an example). The real-time beamforming and signal processing allowing the adaptive control of lesion formation is enabled by a high performance GPU platform (response time within 10 msec). We present results from a series of experiments in bovine cardiac tissue demonstrating the robustness and increased speed of volumetric lesion formation for a range of clinically-relevant exposures. Gross histology demonstrate clearly that adaptive lesion formation results in tissue damage consistent with the size of the focal spot and the raster scan in 3 dimensions. In contrast, uncontrolled volumetric lesions exhibit significant pre-focal buildup due to excessive exposure from multiple full-exposure HIFU shots. Stopping or reducing the HIFU exposure upon the detection of such an

  20. SPHERICAL COVERAGE DUAL MODE SENSOR FOR UAS SEPARATION ASSURANCE, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Proposed is a dual-mode sensor for use aboard unmanned aircraft for safe operation in the NAS that: 1. Incorporates high resolution Millimeter Wave radar with high...

  1. Performance Evaluation of Three-Level Z-Source Inverters Under Semiconductor Failure Conditions

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, P.C.; Vilathgamuwa, D.M.

    2007-01-01

    reconfigure the gating signals in order to tolerate the failed semiconductor devices without significantly decreasing the ac output quality and amplitude by properly using the inherent boost characteristic of Z-source network. In addition, the Z-source dual inverters can maintain the zero common mode voltage...... under semiconductor failure conditions, which is the unique characteristic attained by the dual inverters only. Lastly, all theoretical findings are verified in PLECS simulations....

  2. A Simple Differential Mode EMI Suppressor for the LLCL-Filter-Based Single-Phase Grid-Tied Transformerless Inverter

    DEFF Research Database (Denmark)

    Ji, Junhao; Wu, Weimin; He, Yuanbin

    2015-01-01

    The single-phase power converter topologies evolving of photovoltaic applications are still including passive filters, like the LCLor LLCL-filter. Compared with the LCL-filter, the total inductance of the LLCL-filter can be reduced a lot. However, due to the resonant inductor in series...... with the bypass capacitor, the differential mode (DM) electromagnetic interference (EMI) noise attenuation of an LLCL-filter-based grid-tied inverter declines. Conventionally, a capacitor was inserted in parallel with the LC resonant circuit branch of the LLCL-filter to suppress the DM EMI noise. In order...... to achieve a small value of capacitor as well as to minimize the additional reactive power, a novel simple DM EMI suppressor for the LLCL-filter-based system is proposed. The characters of two kinds of DM EMI suppressor are analyzed and compared in detail. Simulations and experiments on a 0.5-kW 110-V/50-Hz...

  3. Design of Dual-Mode Local Oscillators Using CMOS Technology for Motion Detection Sensors.

    Science.gov (United States)

    Ha, Keum-Won; Lee, Jeong-Yun; Kim, Jeong-Geun; Baek, Donghyun

    2018-04-01

    Recently, studies have been actively carried out to implement motion detecting sensors by applying radar techniques. Doppler radar or frequency-modulated continuous wave (FMCW) radar are mainly used, but each type has drawbacks. In Doppler radar, no signal is detected when the movement is stopped. Also, FMCW radar cannot function when the detection object is near the sensor. Therefore, by implementing a single continuous wave (CW) radar for operating in dual-mode, the disadvantages in each mode can be compensated for. In this paper, a dual mode local oscillator (LO) is proposed that makes a CW radar operate as a Doppler or FMCW radar. To make the dual-mode LO, a method that controls the division ratio of the phase locked loop (PLL) is used. To support both radar mode easily, the proposed LO is implemented by adding a frequency sweep generator (FSG) block to a fractional-N PLL. The operation mode of the LO is determined by according to whether this block is operating or not. Since most radar sensors are used in conjunction with microcontroller units (MCUs), the proposed architecture is capable of dual-mode operation by changing only the input control code. In addition, all components such as VCO, LDO, and loop filter are integrated into the chip, so complexity and interface issues can be solved when implementing radar sensors. Thus, the proposed dual-mode LO is suitable as a radar sensor.

  4. Design of Dual-Mode Local Oscillators Using CMOS Technology for Motion Detection Sensors

    Directory of Open Access Journals (Sweden)

    Keum-Won Ha

    2018-04-01

    Full Text Available Recently, studies have been actively carried out to implement motion detecting sensors by applying radar techniques. Doppler radar or frequency-modulated continuous wave (FMCW radar are mainly used, but each type has drawbacks. In Doppler radar, no signal is detected when the movement is stopped. Also, FMCW radar cannot function when the detection object is near the sensor. Therefore, by implementing a single continuous wave (CW radar for operating in dual-mode, the disadvantages in each mode can be compensated for. In this paper, a dual mode local oscillator (LO is proposed that makes a CW radar operate as a Doppler or FMCW radar. To make the dual-mode LO, a method that controls the division ratio of the phase locked loop (PLL is used. To support both radar mode easily, the proposed LO is implemented by adding a frequency sweep generator (FSG block to a fractional-N PLL. The operation mode of the LO is determined by according to whether this block is operating or not. Since most radar sensors are used in conjunction with microcontroller units (MCUs, the proposed architecture is capable of dual-mode operation by changing only the input control code. In addition, all components such as VCO, LDO, and loop filter are integrated into the chip, so complexity and interface issues can be solved when implementing radar sensors. Thus, the proposed dual-mode LO is suitable as a radar sensor.

  5. Weak turbulence theory of ion temperature gradient modes for inverted density plasmas

    International Nuclear Information System (INIS)

    Hahm, T.S.; Tang, W.M.

    1989-09-01

    Typical profiles measured in H-mode (''high confinement'') discharges from tokamaks such as JET and DIII-D suggest that the ion temperature gradient instability threshold parameter η i (≡dlnT i /dlnn i ) could be negative in many cases. Previous linear theoretical calculations have established the onset conditions for these negative η i -modes and the fact that their growth rate is much smaller than their real frequency over a wide range of negative η i values. This has motivated the present nonlinear weak turbulence analysis to assess the relevance of such instabilities for confinement in H-mode plasmas. The nonlinear eigenmode equation indicates that the 3-wave coupling to shorter wavelength modes is the dominant nonlinear saturation mechanism. It is found that both the saturation level for these fluctuations and the magnitude of the associated ion thermal diffusivity are considerably smaller than the strong turbulence mixing length type estimates for the more conventional positive-η i -instabilities. 19 refs., 3 figs

  6. Dual comb generation from a mode-locked fiber laser with orthogonally polarized interlaced pulses.

    Science.gov (United States)

    Akosman, Ahmet E; Sander, Michelle Y

    2017-08-07

    Ultra-high precision dual-comb spectroscopy traditionally requires two mode-locked, fully stabilized lasers with complex feedback electronics. We present a novel mode-locked operation regime in a thulium-holmium co-doped fiber laser, a frequency-halved state with orthogonally polarized interlaced pulses, for dual comb generation from a single source. In a linear fiber laser cavity, an ultrafast pulse train composed of co-generated, equal intensity and orthogonally polarized consecutive pulses at half of the fundamental repetition rate is demonstrated based on vector solitons. Upon optical interference of the orthogonally polarized pulse trains, two stable microwave RF beat combs are formed, effectively down-converting the optical properties into the microwave regime. These co-generated, dual polarization interlaced pulse trains, from one all-fiber laser configuration with common mode suppression, thus provide an attractive compact source for dual-comb spectroscopy, optical metrology and polarization entanglement measurements.

  7. Studies on biogas-fuelled compression ignition engine under dual fuel mode.

    Science.gov (United States)

    Mahla, Sunil Kumar; Singla, Varun; Sandhu, Sarbjot Singh; Dhir, Amit

    2018-04-01

    Experimental investigation has been carried out to utilize biogas as an alternative source of energy in compression ignition (CI) engine under dual fuel operational mode. Biogas was inducted into the inlet manifold at different flow rates along with fresh air through inlet manifold and diesel was injected as a pilot fuel to initiate combustion under dual fuel mode. The engine performance and emission characteristics of dual fuel operational mode were analyzed at different biogas flow rates and compared with baseline conventional diesel fuel. Based upon the improved performance and lower emission characteristics under the dual fuel operation, the optimum flow rate of biogas was observed to be 2.2 kg/h. The lower brake thermal efficiency (BTE) and higher brake-specific energy consumption (BSEC) were noticed with biogas-diesel fuel under dual fuel mode when compared with neat diesel operation. Test results showed reduced NO x emissions and smoke opacity level in the exhaust tailpipe emissions. However, higher hydrocarbon (HC) and carbon monoxide (CO) emissions were noticed under dual fuel mode at entire engine loads when compared with baseline fossil petro-diesel. Hence, the use of low-cost gaseous fuel such as biogas would be an economically viable proposition to address the current and future problems of energy scarcity and associated environmental concerns.

  8. Generalized coupling resonance modeling, analysis, and active damping of multi-parallel inverters in microgrid operating in grid-connected mode

    DEFF Research Database (Denmark)

    Chen, Zhiyong; Chen, Yandong; Guerrero, Josep M.

    2016-01-01

    This paper firstly presents an equivalent coupling circuit modeling of multi-parallel inverters in microgrid operating in grid-connected mode. By using the model, the coupling resonance phenomena are explicitly investigated through the mathematical approach, and the intrinsic and extrinsic...

  9. Development of a magnet power supply with sub-ppm ripple performance for J-PARC with a novel common-mode rejection method with an NPC inverter

    International Nuclear Information System (INIS)

    Koseki, K.; Kurimoto, Y.

    2014-01-01

    The mechanism that generates common-mode noise in inverter circuits, which are widely used in magnet power supplies, was evaluated by a circuit simulation. By following asymmetric operational sequences, pulsed voltage is applied to the parasitic capacitance of power cables that causes a common-mode current at each switching period of the semiconductor switches. Common-mode noise was also found to disturb the normal-mode excitation current by inducing higher frequency components in the applied voltage to the magnet. To eliminate the disturbing effect by the common-mode noise, a newly developed operational method that uses a neutral point clamped, NPC, inverter with reduced switching sequences was evaluated both by a circuit simulation and experimentally. The operational method for the NPC inverter could sufficiently reduce the common-mode noise. A high-power test operation performed using 16 bending magnets at the J-PARC facility achieved a ripple of less than 1 ppm in the excitation current

  10. Development of a magnet power supply with sub-ppm ripple performance for J-PARC with a novel common-mode rejection method with an NPC inverter

    Energy Technology Data Exchange (ETDEWEB)

    Koseki, K., E-mail: kunio.koseki@kek.jp; Kurimoto, Y.

    2014-05-21

    The mechanism that generates common-mode noise in inverter circuits, which are widely used in magnet power supplies, was evaluated by a circuit simulation. By following asymmetric operational sequences, pulsed voltage is applied to the parasitic capacitance of power cables that causes a common-mode current at each switching period of the semiconductor switches. Common-mode noise was also found to disturb the normal-mode excitation current by inducing higher frequency components in the applied voltage to the magnet. To eliminate the disturbing effect by the common-mode noise, a newly developed operational method that uses a neutral point clamped, NPC, inverter with reduced switching sequences was evaluated both by a circuit simulation and experimentally. The operational method for the NPC inverter could sufficiently reduce the common-mode noise. A high-power test operation performed using 16 bending magnets at the J-PARC facility achieved a ripple of less than 1 ppm in the excitation current.

  11. Ultrabright femtosecond source of biphotons based on a spatial mode inverter.

    Science.gov (United States)

    Jarutis, Vygandas; Juodkazis, Saulius; Mizeikis, Vygantas; Sasaki, Keiji; Misawa, Hiroaki

    2005-02-01

    A method of enhancing the efficiency of entangled biphoton sources based on a type II femtosecond spontaneous parametric downconversion (SPDC) process is proposed and implemented experimentally. Enhancement is obtained by mode inversion of one of the SPDC output beams, which allows the beams to overlap completely, thus maximizing the number of SPDC photon pairs with optimum spatiotemporal overlap. By use of this method, biphoton count rates as high as 16 kHz from a single 0.5-mm-long beta-barium borate crystal pumped by second-harmonic radiation from a Ti:sapphire laser were obtained.

  12. Design of dual-mode optical fibres for the FTTH applications

    Science.gov (United States)

    Chen, Ming-Yang; Li, Yu-Rong; Zhang, Yin; Zhu, Yuan-Feng; Zhang, Yong-Kang; Zhou, Jun

    2011-01-01

    We present in this article a proposal and design for dual-mode optical fibres for fibre-to-the-home applications. High-order modes in the fibre can be effectively suppressed by the connection of the fibre with standard single-mode optical fibres at the two ends of the fibre. The alignment tolerance at the splicing process is presented. In particular, a low bending loss operation with low splice loss is demonstrated using the proposed technique.

  13. Design of dual-mode optical fibres for the FTTH applications

    International Nuclear Information System (INIS)

    Chen, Ming-Yang; Li, Yu-Rong; Zhang, Yin; Zhu, Yuan-Feng; Zhang, Yong-Kang; Zhou, Jun

    2011-01-01

    We present in this article a proposal and design for dual-mode optical fibres for fibre-to-the-home applications. High-order modes in the fibre can be effectively suppressed by the connection of the fibre with standard single-mode optical fibres at the two ends of the fibre. The alignment tolerance at the splicing process is presented. In particular, a low bending loss operation with low splice loss is demonstrated using the proposed technique

  14. A 380pW Dual Mode Optical Wake-up Receiver with Ambient Noise Cancellation.

    Science.gov (United States)

    Lim, Wootaek; Jang, Taekwang; Lee, Inhee; Kim, Hun-Seok; Sylvester, Dennis; Blaauw, David

    2016-06-01

    We present a sub-nW optical wake-up receiver for wireless sensor nodes. The wake-up receiver supports dual mode operation for both ultra-low standby power and high data rates, while canceling ambient in-band noise. In 0.18µm CMOS the receiver consumes 380pW in always-on wake-up mode and 28.1µW in fast RX mode at 250kbps.

  15. Dual-mode optical microscope based on single-pixel imaging

    OpenAIRE

    Rodríguez Jiménez, Angel David; Clemente Pesudo, Pedro Javier; Tajahuerce, Enrique; Lancis Sáez, Jesús

    2016-01-01

    We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no moving parts, works by sequential projection of a set of binary intensity patterns onto the sample that are codified onto a modified commercial DMD...

  16. [Application of second generation dual-source computed tomography dual-energy scan mode in detecting pancreatic adenocarcinoma].

    Science.gov (United States)

    Xue, Hua-dan; Liu, Wei; Sun, Hao; Wang, Xuan; Chen, Yu; Su, Bai-yan; Sun, Zhao-yong; Chen, Fang; Jin, Zheng-yu

    2010-12-01

    To analyze the clinical value of multiple sequences derived from dual-source computed tomography (DSCT) dual-energy scan mode in detecting pancreatic adenocarcinoma. Totally 23 patients with clinically or pathologically diagnosed pancreatic cancer were enrolled in this retrospective study. DSCT (Definition Flash) was used and dual-energy scan mode was used in their pancreatic parenchyma phase scan (100kVp/230mAs and Sn140kVp/178mAs) . Mono-energetic 60kev, mono-energetic 80kev, mono-energetic 100kev, mono-energetic 120kev, linear blend image, non-linear blend image, and iodine map were acquired. pancreatic parenchyma-tumor CT value difference, ratio of tumor to pancreatic parenchyma, and pancreatic parenchyma-tumor contrast to noise ratio were calculated. One-way ANOVA was used for the comparison of diagnostic values of the above eight different dual-energy derived sequences for pancreatic cancer. The pancreatic parenchyma-tumor CT value difference, ratio of tumor to pancreatic parenchyma, and pancreatic parenchyma-tumor contrast to noise ratio were significantly different among eight sequences (P<0.05) . Mono-energetic 60kev image showed the largest parenchyma-tumor CT value [ (77.53 ± 23.42) HU] , and iodine map showed the lowest tumor/parenchyma enhancement ratio (0.39?0.12) and the largest contrast to noise ratio (4.08 ± 1.46) . Multiple sequences can be derived from dual-energy scan mode with DSCT via multiple post-processing methods. Integration of these sequences may further improve the sensitivity of the multislice spiral CT in the diagnosis of pancreatic cancer.

  17. Dual-Mode Operation of an Optical Lattice Clock Using Strontium and Ytterbium Atoms.

    Science.gov (United States)

    Akamatsu, Daisuke; Kobayashi, Takumi; Hisai, Yusuke; Tanabe, Takehiko; Hosaka, Kazumoto; Yasuda, Masami; Hong, Feng-Lei

    2018-06-01

    We have developed an optical lattice clock that can operate in dual modes: a strontium (Sr) clock mode and an ytterbium (Yb) clock mode. Dual-mode operation of the Sr-Yb optical lattice clock is achieved by alternately cooling and trapping 87 Sr and 171 Yb atoms inside the vacuum chamber of the clock. Optical lattices for Sr and Yb atoms were arranged with horizontal and vertical configurations, respectively, resulting in a small distance of the order of between the trapped Sr and Yb atoms. The 1 S 0 - 3 P 0 clock transitions in the trapped atoms were interrogated in turn and the clock lasers were stabilized to the transitions. We demonstrated the frequency ratio measurement of the Sr and Yb clock transitions by using the dual-mode operation of the Sr-Yb optical lattice clock. The dual-mode operation can reduce the uncertainty of the blackbody radiation shift in the frequency ratio measurement, because both Sr and Yb atoms share the same blackbody radiation.

  18. A flexible dual-mode proximity sensor based on cooperative sensing for robot skin applications

    Science.gov (United States)

    Huang, Ying; Cai, Xia; Kan, Wenqing; Qiu, Shihua; Guo, Xiaohui; Liu, Caixia; Liu, Ping

    2017-08-01

    A flexible dual-mode proximity sensor has been designed and implemented, which is capable of combining capacitive-resistive detection in this paper. The capacitive type proximity sensor detecting is defined as mode-C, and the resistive type proximity sensor detecting is defined as mode-R. The characteristics of the proximity sensor are as follows: (1) the theoretical mode is developed which indicates that this proximity sensor can reflect proximity information accurately; (2) both sensing modes are vertically integrated into a sandwich-like chip with an 8 mm × 12 mm unit area. The thickness of a mode-R sensing material (graphene nanoplatelets) and mode-C dielectric (the mixture of carbon black and silicone rubber) is 1 mm and 2.5 mm, respectively; (3) for mode-R, the linearity of temperature-resistance curve can achieve 0.998 in the temperature range from 25°C to 65°C. And for mode-C, various materials can be successfully detected with fast response and high reversibility. Meanwhile, the study compensated the influence of object temperature to ensure mode-C properly works. A cooperative sensing test shows that R-C dual modes sense effectively which can enlarge the sensing distance compared with the single mode proximity sensor. The fabrication of this sensor is convenient, and the integrity of a flexible sandwich-like structure based on dual modes is beneficial to form arrays, which is suitable to be used in skin-like sensing applications.

  19. Dual-mode ultraflow access networks: a hybrid solution for the access bottleneck

    Science.gov (United States)

    Kazovsky, Leonid G.; Shen, Thomas Shunrong; Dhaini, Ahmad R.; Yin, Shuang; De Leenheer, Marc; Detwiler, Benjamin A.

    2013-12-01

    Optical Flow Switching (OFS) is a promising solution for large Internet data transfers. In this paper, we introduce UltraFlow Access, a novel optical access network architecture that offers dual-mode service to its end-users: IP and OFS. With UltraFlow Access, we design and implement a new dual-mode control plane and a new dual-mode network stack to ensure efficient connection setup and reliable and optimal data transmission. We study the impact of the UltraFlow system's design on the network throughput. Our experimental results show that with an optimized system design, near optimal (around 10 Gb/s) OFS data throughput can be attained when the line rate is 10Gb/s.

  20. Design and Implementation of Dual-Mode Wireless Video Monitoring System

    Directory of Open Access Journals (Sweden)

    BAO Song-Jian

    2014-10-01

    Full Text Available Dual-mode wireless video transmission has two major problems. Firstly, one is time delay difference bringing about asynchronous reception decoding frame error phenomenon; secondly, dual-mode network bandwidth inconformity causes scheduling problem. In order to solve above two problems, a kind of TD-SCDMA/CDMA20001x dual-mode wireless video transmission design method is proposed. For the solution of decoding frame error phenomenon, the design puts forward adding frame identification and packet preprocessing at the sending and synchronizing combination at the receiving end. For the solution of scheduling problem, the wireless communication channel cooperative work and video data transmission scheduling management algorithm is proposed in the design.

  1. Direct model-based predictive control scheme without cost function for voltage source inverters with reduced common-mode voltage

    Science.gov (United States)

    Kim, Jae-Chang; Moon, Sung-Ki; Kwak, Sangshin

    2018-04-01

    This paper presents a direct model-based predictive control scheme for voltage source inverters (VSIs) with reduced common-mode voltages (CMVs). The developed method directly finds optimal vectors without using repetitive calculation of a cost function. To adjust output currents with the CMVs in the range of -Vdc/6 to +Vdc/6, the developed method uses voltage vectors, as finite control resources, excluding zero voltage vectors which produce the CMVs in the VSI within ±Vdc/2. In a model-based predictive control (MPC), not using zero voltage vectors increases the output current ripples and the current errors. To alleviate these problems, the developed method uses two non-zero voltage vectors in one sampling step. In addition, the voltage vectors scheduled to be used are directly selected at every sampling step once the developed method calculates the future reference voltage vector, saving the efforts of repeatedly calculating the cost function. And the two non-zero voltage vectors are optimally allocated to make the output current approach the reference current as close as possible. Thus, low CMV, rapid current-following capability and sufficient output current ripple performance are attained by the developed method. The results of a simulation and an experiment verify the effectiveness of the developed method.

  2. Simulation of Processes in Dual Three-Phase System on the Base of Four Inverters with Synchronized Modulation

    OpenAIRE

    Oleschuk, Valentin; Grandi, Gabriele; Sanjeevikumar, Padmanaban

    2011-01-01

    Novel method of space-vector-based pulse-width modulation (PWM) has been disseminated for synchronous control of four inverters feeding six-phase drive on the base of asymmetrical induction motor which has two sets of windings spatially shifted by 30 electrical degrees. Basic schemes of synchronized PWM, applied for control of four separate voltage-source inverters, allow both continuous phase voltages synchronization in the system and required power sharing between DC sources. Detailed MATLA...

  3. Active power filter for harmonic compensation using a digital dual-mode-structure repetitive control approach

    DEFF Research Database (Denmark)

    Zou, Zhixiang; Wang, Zheng; Cheng, Ming

    2012-01-01

    This paper presents an digital dual-mode-structure repetitive control approach for the single-phase shunt active power filter (APF), which aims to enhance the tracking ability and eliminate arbitrary order harmonic. The proposed repetitive control scheme blends the characteristics of both odd......-harmonic repetitive control and even-harmonic repetitive control. Moreover, the convergence rate is faster than conventional repetitive controller. Additionally, the parameters have been designed and optimized for the dual-mode structure repetitive control to improve the performance of APF system. Experimental...

  4. Coordination in the Decentralized Assembly System with Dual Supply Modes

    Directory of Open Access Journals (Sweden)

    Xu Guan

    2013-01-01

    Full Text Available This paper investigates a decentralized assembly system that consists of one assembler and two independent suppliers; wherein one supplier is perfectly reliable for the production, while the other generates yield uncertainty. Facing the random market demand, the assembler has to order the components from one supplier in advance and meanwhile requires the other supplier to deliver the components under VMI mode. We construct a Nash game between the supplier and the assembler so as to derive their equilibrium procurement/production strategies. The results show that the channel’s performance is highly undermined by the decentralization between players and also the combination of two supply modes. Compared to the centralized system, we propose an advance payment contract to perfectly coordinate the supply chain performance. The numerical examples indicate some management implications on the supply mode comparison and sensitivity analysis.

  5. Tunable single and dual mode operation of an external cavity quantum-dot injection laser

    International Nuclear Information System (INIS)

    Biebersdorf, A; Lingk, C; De Giorgi, M; Feldmann, J; Sacher, J; Arzberger, M; Ulbrich, C; Boehm, G; Amann, M-C; Abstreiter, G

    2003-01-01

    We investigate quantum-dot (QD) lasers in an external cavity using Littrow and Littman configurations. Here, we report on a continuously tunable QD laser with a broad tuning range from 1047 to 1130 nm with high stability and efficient side mode suppression. The full-width at half-maximum of the laser line is 0.85 nm determined mainly by the quality of the external grating. This laser can be operated in a dual-mode modus, where the mode-spacing can be tuned continuously between 1.1 and 34 nm. Simultaneous emission of the two laser modes is shown by sum frequency generation experiments

  6. An overmoded relativistic backward wave oscillator with efficient dual-mode operation

    International Nuclear Information System (INIS)

    Xiao, Renzhen; Li, Jiawei; Bai, Xianchen; Song, Zhimin; Teng, Yan; Ye, Hu; Li, Xiaoze; Sun, Jun; Chen, Changhua; Zhang, Xiaowei

    2014-01-01

    A dual-mode operation mechanism in an overmoded relativistic backward wave oscillator is presented. The electron beam interacts with the −1st space harmonic of TM 01 mode synchronously in the slow wave structure. Then the backward propagating TM 01 mode is converted to the forward propagating TM 02 mode. As the phase velocity of the volume harmonic of TM 02 mode is about twice that of the surface harmonic of TM 01 mode, the TM 02 mode also plays an important role in the high-power microwave generation. Particle-in-cell simulation shows that an efficiency of 48% and a significant improvement of the power capacity have been obtained

  7. A Dual Mode Propulsion System for Small Satellite Applications

    Directory of Open Access Journals (Sweden)

    Kevin R. Gagne

    2018-05-01

    Full Text Available This study focused on the development of a chemical micropropulsion system suitable for primary propulsion and/or attitude control for a nanosatellite. Due to the limitations and expense of current micropropulsion technologies, few nanosatellites with propulsion have been launched to date; however, the availability of such a propulsion system would allow for new nanosatellite mission concepts, such as deep space exploration, maneuvering in low gravity environments and formation flying. This work describes the design of “dual mode” monopropellant/bipropellant microthruster prototype that employs a novel homogeneous catalysis scheme. Results from prototype testing are reported that validate the concept. The micropropulsion system is designed to be fabricated using a combination of additively-manufactured and commercial off the shelf (COTS parts along with non-toxic fuels, thus making it a low-cost and environmentally-friendly option for future nanosatellite missions.

  8. Switchable dual-wavelength single-longitudinal-mode erbium fiber laser utilizing a dual-ring scheme with a saturable absorber

    Science.gov (United States)

    Yang, Zi-Qing; Huang, Tzu-Jung; Chang, Yao-Jen; Yeh, Chien-Hung; Chow, Chi-Wai; Chen, Jing-Heng; Chen, Kun-Huang

    2018-06-01

    In this work, we propose and demonstrate a switchable dual-wavelength erbium-doped fiber (EDF) ring laser with stable single-longitudinal-mode (SLM) output. Here, a dual-ring (DR) structure with an unpumped EDF of 2 m is designed to achieve SLM oscillation. Five fiber Bragg gratings (FBGs) are applied in the laser cavity serving as the reflective element to generate different dual-wavelength outputs. In the measurement, six sets of generated dual-wavelengths with various mode-spacing (Δλ) can be achieved via the five FBGs. Additionally, the stability performance of the proposed EDF DR laser is also demonstrated.

  9. A dual-mode proximity sensor with integrated capacitive and temperature sensing units

    International Nuclear Information System (INIS)

    Qiu, Shihua; Huang, Ying; He, Xiaoyue; Sun, Zhiguang; Liu, Ping; Liu, Caixia

    2015-01-01

    The proximity sensor is one of the most important devices in the field of robot application. It can accurately provide the proximity information to assistant robots to interact with human beings and the external environment safely. In this paper, we have proposed and demonstrated a dual-mode proximity sensor composed of capacitive and resistive sensing units. We defined the capacitive type proximity sensor perceiving the proximity information as C-mode and the resistive type proximity sensor detecting as R-mode. Graphene nanoplatelets (GNPs) were chosen as the R-mode sensing material because of its high performance. The dual-mode proximity sensor presents the following features: (1) the sensing distance of the dual-mode proximity sensor has been enlarged compared with the single capacitive proximity sensor in the same geometrical pattern; (2) experiments have verified that the proposed sensor can sense the proximity information of different materials; (3) the proximity sensing capability of the sensor has been improved by two modes perceive collaboratively, for a plastic block at a temperature of 60 °C: the R-mode will perceive the proximity information when the distance d between the sensor and object is 6.0–17.0 mm and the C-mode will do that when their interval is 0–2.0 mm; additionally two modes will work together when the distance is 2.0–6.0 mm. These features indicate our transducer is very valuable in skin-like sensing applications. (paper)

  10. Grid to Standalone Transition Motion-Sensorless Dual-Inverter Control of PMSG With Asymmetrical Grid Voltage Sags and Harmonics Filtering

    DEFF Research Database (Denmark)

    Fatu, M.; Blaabjerg, Frede; Boldea, I.

    2014-01-01

    This paper describes a variable-speed motion-sensorless control system for permanent-magnet synchronous generator (PMSG) connected to grid via back-to-back inverters for wind energy generation. The grid-side inverter control system employs proportional-integral (PI) current controllers with cross...... and automatic seamless transfer method from grid connected to stand alone and vice versa. In stand-alone mode, a voltage control scheme with selective harmonic compensation is employed. The PMSG motion-sensorless control system uses an active power controller and a PLL-based observer to estimate the rotor...... and voltage harmonics compensation. While some of the aforementioned issues have been treated rather individually in previous conference publications of the authors, the present paper integrates them into a comprehensive control system of PMSG....

  11. Sliding-Mode Control to Compensate PVT Variations in Dual Core Systems

    NARCIS (Netherlands)

    Pourshaghaghi, H.R.; Fatemi, S.H.; Pineda de Gyvez, J.

    2012-01-01

    In this paper, we present a novel robust sliding-mode controller for stabilizing supply voltage and clock frequency of dual core processors determined by dynamic voltage and frequency scaling (DVFS) methods in the presence of systematic and random variations. We show that maximum rejection for

  12. Spectrally interleaved, comb-mode-resolved spectroscopy using swept dual terahertz combs

    Science.gov (United States)

    Hsieh, Yi-Da; Iyonaga, Yuki; Sakaguchi, Yoshiyuki; Yokoyama, Shuko; Inaba, Hajime; Minoshima, Kaoru; Hindle, Francis; Araki, Tsutomu; Yasui, Takeshi

    2014-01-01

    Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10-7 in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

  13. Spectrally interleaved, comb-mode-resolved spectroscopy using swept dual terahertz combs.

    Science.gov (United States)

    Hsieh, Yi-Da; Iyonaga, Yuki; Sakaguchi, Yoshiyuki; Yokoyama, Shuko; Inaba, Hajime; Minoshima, Kaoru; Hindle, Francis; Araki, Tsutomu; Yasui, Takeshi

    2014-01-22

    Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10(-7) in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

  14. Stabilization of self-mode-locked quantum dash lasers by symmetric dual-loop optical feedback

    Science.gov (United States)

    Asghar, Haroon; Wei, Wei; Kumar, Pramod; Sooudi, Ehsan; McInerney, John. G.

    2018-02-01

    We report experimental studies of the influence of symmetric dual-loop optical feedback on the RF linewidth and timing jitter of self-mode-locked two-section quantum dash lasers emitting at 1550 nm. Various feedback schemes were investigated and optimum levels determined for narrowest RF linewidth and low timing jitter, for single-loop and symmetric dual-loop feedback. Two symmetric dual-loop configurations, with balanced and unbalanced feedback ratios, were studied. We demonstrate that unbalanced symmetric dual loop feedback, with the inner cavity resonant and fine delay tuning of the outer loop, gives narrowest RF linewidth and reduced timing jitter over a wide range of delay, unlike single and balanced symmetric dual-loop configurations. This configuration with feedback lengths 80 and 140 m narrows the RF linewidth by 4-67x and 10-100x, respectively, across the widest delay range, compared to free-running. For symmetric dual-loop feedback, the influence of different power split ratios through the feedback loops was determined. Our results show that symmetric dual-loop feedback is markedly more effective than single-loop feedback in reducing RF linewidth and timing jitter, and is much less sensitive to delay phase, making this technique ideal for applications where robustness and alignment tolerance are essential.

  15. Frustration of Bragg reflection by cooperative dual-mode interference: a new mode of optical propagation.

    Science.gov (United States)

    Yariv, A

    1998-12-01

    A new optical mode of propagation is described, which is the natural eigenmode (supermode) of a fiber (or any optical waveguide) with two cospatial periodic gratings. The mode frustrates the backward Bragg scattering from the grating by destructive interference of its two constituent submodes (which are eigenmodes of a uniform waveguide). It can be used in a new type of spatial mode conversion in optical guides.

  16. Derivation of the threshold condition for the ion temperature gradient mode with an inverted density profile from a simple physics picture

    Science.gov (United States)

    Jhang, Hogun

    2018-05-01

    We show that the threshold condition for the toroidal ion temperature gradient (ITG) mode with an inverted density profile can be derived from a simple physics argument. The key in this picture is that the density inversion reduces the ion compression due to the ITG mode and the electron drift motion mitigates the poloidal potential build-up. This condition reproduces the same result that has been reported from a linear gyrokinetic calculation [T. S. Hahm and W. M. Tang, Phys. Fluids B 1, 1185 (1989)]. The destabilizing role of trapped electrons in toroidal geometry is easily captured in this picture.

  17. Analysis of dual-mode lasing characteristics in a 1310-nm optically injected quantum dot distributed feedback laser

    Science.gov (United States)

    Raghunathan, R.; Olinger, J.; Hurtado, A.; Grillot, F.; Kovanis, V.; Lester, L. F.

    2015-03-01

    Recent work has shown the Quantum Dot (QD) material system to be well-suited to support dual-mode lasing. In particular, optical injection from a master laser (ML) into the residual Fabry-Perot (FP) modes of a 1310 nm Quantum Dot Distributed Feedback (QD-DFB) laser has been recently demonstrated to offer a highly reliable platform for stable dual-mode lasing operation. External controls on the ML, such as operating temperature and bias current, can be used to precisely adjust the spacing between the two lasing modes. This tunability of modeseparation is very promising for a range of applications requiring the generation of microwave, millimeter wave and terahertz signals. Considering the versatility and utility of such a scheme, it is imperative to acquire a deeper understanding of the factors that influence the dual-mode lasing process, in order to optimize performance. Toward this end, this paper seeks to further our understanding of the optically-injected dual-mode lasing mechanism. For fixed values of optical power injected into each FP residual mode and wavelength detuning, the dual-mode lasing characteristics are analyzed with regard to important system parameters such as the position and the intensity of the injected residual mode (relative to the Bragg and the other residual FP modes of the device) for two similarly-fabricated QD-DFBs. Results indicate that for dual mode lasing spaced less than 5 nm apart, the relative intensity of the injected FP mode and intracavity noise levels are critical factors in determining dual mode lasing behavior. Insight into the dual-mode lasing characteristics could provide an important design guideline for the master and QD-DFB slave laser cavities.

  18. Dual Rotating Rake Measurements of Higher-Order Duct Modes: Validation Using Experimental and Numerical Data

    Science.gov (United States)

    Dahl, Milo D.; Hixon, Duane R.; Sutliff, Daniel L.

    2018-01-01

    A rotating rake mode measurement system was designed to measure acoustic duct modes generated by a fan stage. After analysis of the measured data, the mode coefficient amplitudes and phases were quantified. Early studies using this system found that mode power levels computed from rotating rake measured data would agree with the far-field power levels. However, this agreement required that the sound from the noise sources within the duct propagated outward from the duct exit without reflection and previous studies suggested conditions could exist where significant reflections could occur. This paper shows that mounting a second rake to the rotating system, with an offset in both the axial and the azimuthal directions, measures the data necessary to determine the modes propagating in both directions within a duct. The rotating rake data analysis technique was extended to include the data measured by the second rake. The analysis resulted in a set of circumferential mode coefficients at each of the two rake microphone locations. Radial basis functions were then least-squares fit to this data to obtain the radial mode coefficients for the modes propagating in both directions within the duct while accounting for the presence of evanescent modes. The validation of the dual-rotating-rake measurements was conducted using data from a combination of experiments and numerical calculations to compute reflection coefficients and other mode coefficient ratios. Compared to results from analytical and numerical computations, the results from dual-rotating-rake measured data followed the expected trends when frequency, mode number, and duct termination geometry were changed.

  19. Carbon Nanodots as Dual-Mode Nanosensors for Selective Detection of Hydrogen Peroxide

    Science.gov (United States)

    Shen, Cheng-Long; Su, Li-Xia; Zang, Jin-Hao; Li, Xin-Jian; Lou, Qing; Shan, Chong-Xin

    2017-07-01

    Hydrogen peroxide (H2O2) is an important product of oxidase-based enzymatic reactions, such as glucose/glucose oxidase (GOD) reaction. Therefore, the probing of generated H2O2 for achieving the detection of various carbohydrates and their oxidases is very significative. Herein, we report one kind of dual-emission carbon nanodots (CDs) that can serve as novel dual-mode nanosensors with both fluorometric and colorimetric output for the selective detection of H2O2. The dual-model nanosensors are established only by the undecorated dual-emission CDs, where significant fluorometric and colorimetric changes are observed with the addition of different concentrations of H2O2 in the CD solution, which benefit to the achievement of the naked-eye detection for H2O2. The mechanism of the nanosensors can be attributed to the fact that the external chemical stimuli like hydroxyl radicals from H2O2 bring about the change of surface properties and the aggregation of CDs, which dominate the emission and absorption of CDs. The constructed dual-mode nanosensors exhibit good biocompatibility and high selectivity toward H2O2 with a linear detection range spanning from 0.05 to 0.5 M and allow the detection of H2O2 as low as 14 mM.

  20. Design and analysis of a dual mode CMOS field programmable analog array

    International Nuclear Information System (INIS)

    Cheng Xiaoyan; Yang Haigang; Yin Tao; Wu Qisong; Zhang Hongfeng; Liu Fei

    2014-01-01

    This paper presents a novel field-programmable analog array (FPAA) architecture featuring a dual mode including discrete-time (DT) and continuous-time (CT) operation modes, along with a highly routable connection boxes (CBs) based interconnection lattice. The dual mode circuit for the FPAA is capable of achieving targeted optimal performance in different applications. The architecture utilizes routing switches in a CB not only for the signal interconnection purpose but also for control of the electrical charge transfer required in switched-capacitor circuits. This way, the performance of the circuit in either mode shall not be hampered with adding of programmability. The proposed FPAA is designed and implemented in a 0.18 μm standard CMOS process with a 3.3 V supply voltage. The result from post-layout simulation shows that a maximum bandwidth of 265 MHz through the interconnection network is achieved. The measured results from demonstrated examples show that the maximum signal bandwidth of up to 2 MHz in CT mode is obtained with the spurious free dynamic range of 54 dB, while the signal processing precision in DT mode reaches 96.4%. (semiconductor integrated circuits)

  1. Control algorithms for single inverter dual induction motor system applied to railway traction; Commande algorithmique d'un systeme mono-onduleur bimachine asynchrone destine a la traction ferroviaire

    Energy Technology Data Exchange (ETDEWEB)

    Pena Eguiluz, R.

    2002-11-15

    The goal of this work concerns the modelling and the behaviour characterisation of a single inverter dual induction motor system applied to a railway traction bogie (BB36000) in order to concept its control. First part of this job is dedicated to the detailed description of overall system. The influence analysis of the internal perturbations (motor parameters variation) and, external perturbations (pantograph detachment, adherence loss, stick-slip) of the system have made considering the field oriented control applied to each motor of the bogie (classical traction structure). vi In a second part, a novel propulsion structure is proposed. It is composed by a single pulse-width modulated two level voltage source inverter. It supplies two parallel connected induction motors, which generate the transmitted traction force to the bogie wheels. The locomotive case represents the common load for the two motors. Several co-operative control strategies (CS) are studied. They are: the mean CS, the double mean CS, the master - slave switched CS and, the mean differential CS. In addition, an appropriated electric modes observer structure for these different controls has studied. These controls have validated applying the perturbations to the models using the solver SABER. This special approach is equivalent to quasi-experimentation, because the mechanical and the electrical system components have modelled using MAST language and, the sample control has created by a C code programme in the SABER environment. Third part is dedicated to the mechanical sensor suppression and, its adaptation in the cooperative control strategies. The partial speed reconstruction methods are: the fundamental frequency relation, the mechanical Kalman filter, the variable structure observer and the MRAS. Finally, the hardware system configuration of the experimental realisation is described. (author)

  2. Design and optimisation of dual-mode heat pump systems using natural fluids

    International Nuclear Information System (INIS)

    Zhang Wenling; Klemeš, Jiří Jaromír; Kim, Jin-Kuk

    2012-01-01

    The paper introduces new multi-period modelling and design methodology for dual-mode heat pumps using natural fluids. First, a mathematical model is developed to capture thermodynamic and operating characteristics of dual-mode heat pump systems, subject to different ambient temperatures. The multi-period optimisation framework has been developed to reflect different ambient conditions and its influences on heat pump performance, as well as to determine a system capacity of heat pump which allows systematic economic trade-offs between supplementary heating (or cooling) and operating cost for heat pump. Case study considering three geographical locations with different heating and cooling demands is presented to illustrate the importance of using multi-period optimisation for the design of heat pump systems.

  3. Dual-Mode Dual-Band Microstrip Bandpass Filter Based on Fourth Iteration T-Square Fractal and Shorting Pin

    Directory of Open Access Journals (Sweden)

    E. S. Ahmed

    2012-06-01

    Full Text Available A new class of dual mode microstrip fractal resonator is proposed and developed for miniaturization of the dual band bandpass filter. The perimeter of the proposed resonator is increased by employing fourth iteration T-square fractal shape. Consequently the lower resonant frequency of the filter is decreased without increasing the usable space. The self similarity of the usable structure enables it to produce the two degenerate modes which are coupled using the proper perturbation technique. The shorting pin is placed at the null in the surface current distribution at the center of the resonator. This shorting pin is coactively coupled to the resonant circuit of the resonator, effectively coupled to the lower degenerate mode and reduces the lower edge band resonant frequency. By adjusting the resonator dimensions and the size of the shorting pin, the resonant frequency and the out-of-band rejection around the transmission bands can be controlled to meet the design requirements. The simulated response of the designed filter has two transmission bands, the first band is from 2.34-3.65 GHz with resonant frequencies at 2.47GHz and 3.55GHz, the second band is from 4.37-5.324GHz with resonant frequencies at 4.5GHz and 5.13GHz. In the pass bands, the group delay is less than 0.65 ns. The proposed filter can be applied to WLAN (2.4 GHz and 5.2 GHz and WiMAX (3.5 GHz and Bluetooth and ZigBee (4.9 GHz.

  4. Adaptive super-twisting sliding mode control for a three-phase single-stage grid-connected differential boost inverter based photovoltaic system.

    Science.gov (United States)

    Pati, Akshaya K; Sahoo, N C

    2017-07-01

    This paper presents an adaptive super-twisting sliding mode control (STC) along with double-loop control for voltage tracking performance of three-phase differential boost inverter and DC-link capacitor voltage regulation in grid-connected PV system. The effectiveness of the proposed control strategies are demonstrated under realistic scenarios such as variations in solar insolation, load power demand, grid voltage, and transition from grid-connected to standalone mode etc. Additional supplementary power quality control functions such as harmonic compensation, and reactive power management are also investigated with the proposed control strategy. The results are compared with conventional proportional-integral controller, and PWM sliding mode controller. The system performance is evaluated in simulation and in real-time. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  5. Thermal Optimized Operation of the Single-Phase Full-Bridge PV Inverter under Low Voltage Ride-Through Mode

    DEFF Research Database (Denmark)

    Wang, Huai; Yang, Yongheng; Blaabjerg, Frede

    2013-01-01

    The efficiency of 98% has been reported on transformer-less photovoltaic (PV) inverters and the penetration of grid-connected PV systems is booming as well. In the future, the PV systems are expected to contribute to the grid stability by means of low voltage ride-through operation and grid suppo...

  6. Dual-mode plasmonic nanorod type antenna based on the concept of a trapped dipole.

    Science.gov (United States)

    Panaretos, Anastasios H; Werner, Douglas H

    2015-04-06

    In this paper we theoretically investigate the feasibility of creating a dual-mode plasmonic nanorod antenna. The proposed design methodology relies on adapting to optical wavelengths the principles of operation of trapped dipole antennas, which have been widely used in the low MHz frequency range. This type of antenna typically employs parallel LC circuits, also referred to as "traps", which are connected along the two arms of the dipole. By judiciously choosing the resonant frequency of these traps, as well as their position along the arms of the dipole, it is feasible to excite the λ/2 resonance of both the original dipole as well as the shorter section defined by the length of wire between the two traps. This effectively enables the dipole antenna to have a dual-mode of operation. Our analysis reveals that the implementation of this concept at the nanoscale requires that two cylindrical pockets (i.e. loading volumes) be introduced along the length of the nanoantenna, inside which plasmonic core-shell particles are embedded. By properly selecting the geometry and constitution of the core-shell particle as well as the constitution of the host material of the two loading volumes and their position along the nanorod, the equivalent effect of a resonant parallel LC circuit can be realized. This effectively enables a dual-mode operation of the nanorod antenna. The proposed methodology introduces a compact approach for the realization of dual-mode optical sensors while at the same time it clearly illustrates the inherent tuning capabilities that core-shell particles can offer in a practical framework.

  7. Enhanced Two-Stage Hierarchical Control for a Dual Mode WECS-Based Microgrid

    Directory of Open Access Journals (Sweden)

    Rasool M. Imran

    2018-05-01

    Full Text Available Along with the great benefits of utilizing renewable energy (e.g., wind energy in the power system, there are also some issues, such as increasing the uncertainty and reducing the system inertia. Communication-based centralized control has started to play a significant role in reacting to the aforementioned issues, especially for relatively small systems, such as microgrids. In this context, in this paper, an enhanced communication-based hierarchical control for a dual mode wind energy conversion system-based microgrid is modeled and investigated. The primary stage utilized the P-V/Q-f droop method, which is the preferred droop method to be used in microgrids when the line impedance is mainly resistive. The secondary stage relied on an enhanced methodology for compensating the deviations of voltage and frequency and improving the performance of the microgrid during small and large signal disturbances. Moreover, as this microgrid operates in a dual mode, the mode transition cases from grid-tied mode to autonomous mode and vice versa have been addressed. Thereafter, an improved control scheme for the unplanned outage transition and a modified control scheme for the pre-synchronization and reconnection transition were proposed. Finally, the proposed work was evaluated by the simulation results in MATLAB environment.

  8. Nanodiamond-Manganese dual mode MRI contrast agents for enhanced liver tumor detection.

    Science.gov (United States)

    Hou, Weixin; Toh, Tan Boon; Abdullah, Lissa Nurrul; Yvonne, Tay Wei Zheng; Lee, Kuan J; Guenther, Ilonka; Chow, Edward Kai-Hua

    2017-04-01

    Contrast agent-enhanced magnetic resonance (MR) imaging is critical for the diagnosis and monitoring of a number of diseases, including cancer. Certain clinical applications, including the detection of liver tumors, rely on both T1 and T2-weighted images even though contrast agent-enhanced MR imaging is not always reliable. Thus, there is a need for improved dual mode contrast agents with enhanced sensitivity. We report the development of a nanodiamond-manganese dual mode contrast agent that enhanced both T1 and T2-weighted MR imaging. Conjugation of manganese to nanodiamonds resulted in improved longitudinal and transverse relaxivity efficacy over unmodified MnCl 2 as well as clinical contrast agents. Following intravenous administration, nanodiamond-manganese complexes outperformed current clinical contrast agents in an orthotopic liver cancer mouse model while also reducing blood serum concentration of toxic free Mn 2+ ions. Thus, nanodiamond-manganese complexes may serve as more effective dual mode MRI contrast agent, particularly in cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Dual-Pump CARS Measurements in the University of Virginia's Dual-Mode Scramjet: Configuration "A"

    Science.gov (United States)

    Cutler, Andrew D.; Magnotti, Gaetano; Gallo, Emanuela; Danehy, Paul M.; Rockwell, Robert; Goyne, Christopher P.; McDaniel, James

    2012-01-01

    In this paper we describe efforts to obtain canonical data sets to assist computational modelers in their development of models for the prediction of mixing and combustion in scramjet combustors operating in the ramjet-scramjet transition regime. The CARS technique is employed to acquire temporally and spatially resolved measurements of temperature and species mole-fraction at four planes, one upstream of an H2 fuel injector and three downstream. The technique is described and results are presented for cases with and without chemical reaction. The vibrational energy mode in the heated airstream of the combustor was observed to be frozen at near facility heater conditions and significant nonuniformities in temperature were observed, attributed to nonuniformities of temperature exiting the heater. The measurements downstream of fuel injection show development of mixing and combustion, and are already proving useful to the modelers.

  10. Unidirectional, dual-comb lasing under multiple pulse formation mechanisms in a passively mode-locked fiber ring laser

    OpenAIRE

    Liu, Ya; Zhao, Xin; Hu, Guoqing; Li, Cui; Zhao, Bofeng; Zheng, Zheng

    2016-01-01

    Dual-comb lasers from which asynchronous ultrashort pulses can be simultaneously generated have recently become an interesting research subject. They could be an intriguing alternative to the current dual-laser optical-frequency-comb source with highly sophisticated electronic control systems. If generated through a common light path traveled by all pulses, the common-mode noises between the spectral lines of different pulse trains could be significantly reduced. Therefore, coherent dual-comb...

  11. Bioinspired Flexible and Highly Responsive Dual-Mode Strain/Magnetism Composite Sensor.

    Science.gov (United States)

    Huang, Pei; Li, Yuan-Qing; Yu, Xiao-Guang; Zhu, Wei-Bin; Nie, Shu-Yan; Zhang, Hao; Liu, Jin-Rui; Hu, Ning; Fu, Shao-Yun

    2018-04-04

    The mimicry of human skin to detect both oncoming and physical-contacting object is of great importance in the fields of manufacturing, artificial robots and vehicles, etc. Herein, a novel bioinspired flexible and highly responsive dual-mode strain/magnetism composite sensor, which works via both contact and contactless modes, is first fabricated by incorporating Fe 3 O 4 /silicone system into a carbon fiber aerogel (CFA). The distance dependence of magnetic field endorses the CFA/Fe 3 O 4 /silicone composite possible for spatial sensing due to the introduction of Fe 3 O 4 magnetic nanoparticles. As a result, the as-prepared flexible sensor exhibits precise and real-time response not only to direct-contact compression as usual but also to contactless magnetic field in a wide frequency range from 0.1 to 10 Hz, achieving the maximum variance of 68% and 86% in relative electrical resistance, respectively. The contact and contactless sensing modes of the strain/magnetism sensor are clearly demonstrated by recording the speeds of bicycle riding and walking, respectively. Interestingly, this dual-mode composite sensor exhibits the capacity of identifying the contact and contactless state, which is the first report for flexible sensors. The current protocol is eco-friendly, facile, and thought-provoking for the fabrication of multifunctional sensors.

  12. A reconfigurable frequency-selective surface for dual-mode multi-band filtering applications

    Science.gov (United States)

    Majidzadeh, Maryam; Ghobadi, Changiz; Nourinia, Javad

    2017-03-01

    A reconfigurable single-layer frequency-selective surface (FSS) with dual-mode multi-band modes of operation is presented. The proposed structure is printed on a compact 10 × 10 mm2 FR4 substrate with the thickness of 1.6 mm. A simple square loop is printed on the front side while another one along with two defected vertical arms is deployed on the backside. To realise the reconfiguration, two pin diodes are embedded on the backside square loop. Suitable insertion of conductive elements along with pin diodes yields in dual-mode multi-band rejection of applicable in service frequency ranges. The first operating mode due to diodes' 'ON' state provides rejection of 2.4 GHz WLAN in 2-3 GHz, 5.2/5.8 GHz WLAN and X band in 5-12 GHz, and a part of Ku band in 13.9-16 GHz. In diodes 'OFF' state, the FSS blocks WLAN in 4-7.3 GHz, X band in 8-12.7 GHz as well as part of Ku band in 13.7-16.7 GHz. As well, high attenuation of incident waves is observed by a high shielding effectiveness (SE) in the blocked frequency bands. Also, a stable behaviour against different polarisations and angles of incidence is obtained. Comprehensive studies are conducted on a fabricated prototype to assess its performance from which encouraging results are obtained.

  13. Mini-cavity plasma core reactors for dual-mode space nuclear power/propulsion systems

    International Nuclear Information System (INIS)

    Chow, S.

    1976-01-01

    A mini-cavity plasma core reactor is investigated for potential use in a dual-mode space power and propulsion system. In the propulsive mode, hydrogen propellant is injected radially inward through the reactor solid regions and into the cavity. The propellant is heated by both solid driver fuel elements surrounding the cavity and uranium plasma before it is exhausted out the nozzle. The propellant only removes a fraction of the driver power, the remainder is transferred by a coolant fluid to a power conversion system, which incorporates a radiator for heat rejection. In the power generation mode, the plasma and propellant flows are shut off, and the driver elements supply thermal power to the power conversion system, which generates electricity for primary electric propulsion purposes

  14. Research on Adaptive Dual-Mode Switch Control Strategy for Vehicle Maglev Flywheel Battery

    Directory of Open Access Journals (Sweden)

    Hui Gao

    2015-01-01

    Full Text Available Because of the jamming signal is real-time changeable and control algorithm cannot timely tracking control flywheel rotor, this paper takes vehicle maglev flywheel battery as the research object. One kind of dual-model control strategy is developed based on the analysis of the vibration response impact of the flywheel battery control system. In view of the complex foundation vibration problems of electric vehicles, the nonlinear dynamic simulation model of vehicle maglev flywheel battery is solved. Through analyzing the nonlinear vibration response characteristics, one kind of dual-mode adaptive hybrid control strategy based on H∞ control and unbalance displacement feed-forward compensation control is presented and a real-time switch controller is designed. The reliable hybrid control is implemented, and the stability in the process of real-time switch is solved. The results of this project can provide important basic theory support for the research of vehicle maglev flywheel battery control system.

  15. Sistim Tampilan Jadwal Pesawat Udara Dengan Mode Dual Display Di Bandara Ahmad Yani Semarang

    Directory of Open Access Journals (Sweden)

    Hari Suseno

    2014-02-01

    Full Text Available Schedule for airline passengers is important information that is provided by the airport manager. Airport flight information on the display screen using a media schedule called flight information display system (FIDS. FIDS system comes from two processes that display arrival and departure information. The device comes from the appearance of two separate computer with information for each. The use of two computers that are used to the old system at the airport FIDS devices. This research aims to create an integrated FIDS system device to combine the information into one unified display in dual display mode pattern display (dual view. Design systems using software programming VB6 and hardware modifications applied to design a system FIDS new on view flight schedules. With a centralized system obtained an interactive display schedules for flight schedule. Keywords : FIDS system; Flight schedule; Display  information

  16. 60-GHz Millimeter-wave Over Fiber with Directly Modulated Dual-mode Laser Diode

    Science.gov (United States)

    Tsai, Cheng-Ting; Lin, Chi-Hsiang; Lin, Chun-Ting; Chi, Yu-Chieh; Lin, Gong-Ru

    2016-01-01

    A directly modulated dual-mode laser diode (DMLD) with third-order intermodulation distortion (IMD3) suppression is proposed for a 60-GHz millimeter-wave over fiber (MMWoF) architecture, enabling new fiber-wireless communication access to cover 4-km single-mode-fiber (SMF) and 3-m wireless 16-QAM OFDM transmissions. By dual-mode injection-locking, the throughput degradation of the DMLD is mitigated with saturation effect to reduce its threshold, IMD3 power and relative intensity noise to 7.7 mA, −85 dBm and −110.4 dBc/Hz, respectively, providing huge spurious-free dynamic range of 85.8 dB/Hz2/3. This operation suppresses the noise floor of the DMLD carried QPSK-OFDM spectrum by 5 dB. The optical receiving power is optimized to restrict the power fading effect for improving the bit error rate to 1.9 × 10−3 and the receiving power penalty to 1.1 dB. Such DMLD based hybrid architecture for 60-GHz MMW fiber-wireless access can directly cover the current optical and wireless networks for next-generation indoor and short-reach mobile communications. PMID:27297267

  17. Dual-mode operation of 2D material-base hot electron transistors

    KAUST Repository

    Lan, Yann-Wen; Jr., Carlos M. Torres,; Zhu, Xiaodan; Qasem, Hussam; Adleman, James R.; Lerner, Mitchell B.; Tsai, Shin-Hung; Shi, Yumeng; Li, Lain-Jong; Yeh, Wen-Kuan; Wang, Kang L.

    2016-01-01

    Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (V-CB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (V-CB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.

  18. Dual-mode operation of 2D material-base hot electron transistors.

    Science.gov (United States)

    Lan, Yann-Wen; Torres, Carlos M; Zhu, Xiaodan; Qasem, Hussam; Adleman, James R; Lerner, Mitchell B; Tsai, Shin-Hung; Shi, Yumeng; Li, Lain-Jong; Yeh, Wen-Kuan; Wang, Kang L

    2016-09-01

    Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (VCB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (VCB transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.

  19. Dual-mode operation of 2D material-base hot electron transistors

    KAUST Repository

    Lan, Yann-Wen

    2016-09-01

    Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (V-CB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (V-CB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.

  20. Effect of universal adhesive etching modes on bond strength to dual-polymerizing composite resins.

    Science.gov (United States)

    Michaud, Pierre-Luc; Brown, Matthew

    2018-04-01

    Information is lacking as to the effect on bond strength of the etching modes of universal adhesives when they are used to bond dual-polymerizing composite resins to dentin. The purpose of this in vitro study was to investigate the bonding of dual-polymerizing foundation composite resins to dentin when universal bonding agents are used in self-etch or etch-and-rinse modes. Sixty caries-free, extracted third molar teeth were sectioned transversely in the apical third of the crown and allocated to 12 groups (n=5). Three different bonding agents (Scotchbond Universal, OptiBond XTR, All-Bond Universal) were used to bond 2 different dual-polymerizing composite resins (CompCore AF or CoreFlo DC) to dentin, using 2 different etching approaches (etch-and-rinse or self-etch). The specimens were sectioned into sticks (1×1×8 mm) with a precision saw. The bond strength of the specimens was tested under microtensile force at a crosshead speed of 0.5 mm/min. The data were analyzed using a 3-way ANOVA, a Games-Howell post hoc comparisons model, and Student t tests with Bonferroni corrections (α=.05). In the overall model, the composite resin used had no effect on bond strength (P=.830). The etching protocol by itself also did not have a significant effect (P=.059), although a trend was present. The bonding agent, however, did have an effect (Pcomposite resins to dentin, no single etching protocol is better than another. Depending on which bonding agent is being used, one etching mode may perform better. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  1. A Dual-Mode UWB Wireless Platform with Random Pulse Length Detection for Remote Patient Monitoring

    DEFF Research Database (Denmark)

    Reyes, Carlos; Bisbe, Sergi; Shen, Ming

    2013-01-01

    on a single hardware platform, but it is capable of both monitoring and data transmission. This is achieved by employing a new random pulse length detection method that allows data transmission by using a modulated monitoring signal. To prove the proposed concept a test system has been built, using commercial......This paper presents a dual-mode ultra-wideband platform for wireless Remote Patient Monitoring (RPM). Existing RPM solutions are typically based on two different hardware platforms; one responsible for medical-data monitoring and one to handle data transmission. The proposed RPM topology is based...

  2. Dual-mode endomicroscopy for detection of epithelial dysplasia in the mouth: a descriptive pilot study

    Science.gov (United States)

    Bodenschatz, Nico; Poh, Catherine F.; Lam, Sylvia; Lane, Pierre; Guillaud, Martial; MacAulay, Calum E.

    2017-08-01

    Dual-mode endomicroscopy is a diagnostic tool for early cancer detection. It combines the high-resolution nuclear tissue contrast of fluorescence endomicroscopy with quantified depth-dependent epithelial backscattering as obtained by diffuse optical microscopy. In an in vivo pilot imaging study of 27 oral lesions from 21 patients, we demonstrate the complementary diagnostic value of both modalities and show correlations between grade of epithelial dysplasia and relative depth-dependent shifts in light backscattering. When combined, the two modalities provide diagnostic sensitivity to both moderate and severe epithelial dysplasia in vivo.

  3. Dual-mode switching of a liquid crystal panel for viewing angle control

    Science.gov (United States)

    Baek, Jong-In; Kwon, Yong-Hoan; Kim, Jae Chang; Yoon, Tae-Hoon

    2007-03-01

    The authors propose a method to control the viewing angle of a liquid crystal (LC) panel using dual-mode switching. To realize both wide viewing angle (WVA) characteristics and narrow viewing angle (NVA) characteristics with a single LC panel, the authors use two different dark states. The LC layer can be aligned homogeneously parallel to the transmission axis of the bottom polarizer for WVA dark state operation, while it can be aligned vertically for NVA dark state operation. The authors demonstrated that viewing angle control can be achieved with a single panel without any loss of contrast at the front.

  4. Mode switching control of dual-evaporator air-conditioning systems

    International Nuclear Information System (INIS)

    Lin, J.-L.; Yeh, T.-J.

    2009-01-01

    Modern air-conditioners incorporate variable-speed compressors and variable-opening expansion valves as the actuators for improving cooling performance and energy efficiency. These actuators have to be properly feedback-controlled; otherwise the systems may exhibit even poorer performance than the conventional machines which use fixed-speed compressors and mechanical expansion valves. Particularly for an air-conditioner with multiple evaporators, there are occasions that the machine is operated in a mode that only selected evaporator(s) is(are) turned on, and switching(s) between modes occurs(occur) during the control process. In this case, one needs to have more carefully designed control and switching strategies to ensure the system performance. In this paper, a framework for mode switching control of the dual-evaporator air-conditioning (DEAC) system is proposed. The framework is basically an integration of a controller and a dynamic compensator. The controller, which possesses the flow-distribution capability and assumes both evaporators are on throughout the control process, is intended to provide nominal performance. While mode switching is achieved by varying the reference settings in the controller, the dynamic compensator is used to improve the transient responses immediately after the switching. Experiments indicate that the proposed framework can achieve satisfactory indoor temperature regulation and provide bumpless switching between different modes of operation.

  5. Asynchronous and synchronous dual-wavelength pulse generation in a passively mode-locked fiber laser with a mode-locker.

    Science.gov (United States)

    Hu, Guoqing; Pan, Yingling; Zhao, Xin; Yin, Siyao; Zhang, Meng; Zheng, Zheng

    2017-12-01

    The evolution from asynchronous to synchronous dual-wavelength pulse generation in a passively mode-locked fiber laser is experimentally investigated by tailoring the intracavity dispersion. Through tuning the intracavity-loss-dependent gain profile and the birefringence-induced filter effect, asynchronous dual-wavelength soliton pulses can be generated until the intracavity anomalous dispersion is reduced to ∼8  fs/nm. The transition from asynchronous to synchronous pulse generation is then observed at an elevated pump power in the presence of residual anomalous dispersion, and it is shown that pulses are temporally synchronized at the mode-locker in the cavity. Spectral sidelobes are observed and could be attributed to the four-wave-mixing effect between dual-wavelength pulses at the carbon nanotube mode-locker. These results could provide further insight into the design and realization of such dual-wavelength ultrafast lasers for different applications such as dual-comb metrology as well as better understanding of the inter-pulse interactions in such dual-comb lasers.

  6. Near State Vector Selection-Based Model Predictive Control with Common Mode Voltage Mitigation for a Three-Phase Four-Leg Inverter

    Directory of Open Access Journals (Sweden)

    Abdul Mannan Dadu

    2017-12-01

    Full Text Available A high computational burden is required in conventional model predictive control, as all of the voltage vectors of a power inverter are used to predict the future behavior of the system. Apart from that, the common mode voltage (CMV of a three-phase four-leg inverter utilizes up to half of the DC-link voltage due to the use of all of the available voltage vectors. Thus, this paper proposes a near state vector selection-based model predictive control (NSV-MPC scheme to mitigate the CMV and reduce computational burden. In the proposed technique, only six active voltage vectors are used in the predictive model, and the vectors are selected based on the position of the future reference vector. In every sampling period, the position of the reference current is used to detect the voltage vectors surrounding the reference voltage vector. Besides the six active vectors, one of the zero vectors is also used. The proposed technique is compared with the conventional control scheme in terms of execution time, CMV variation, and load current ripple in both simulation and an experimental setup. The LabVIEW Field programmable gate array rapid prototyping controller is used to validate the proposed control scheme experimentally, and demonstrate that the CMV can be bounded within one-fourth of the DC-link voltage.

  7. SERS-Fluorescence Dual-Mode pH-Sensing Method Based on Janus Microparticles.

    Science.gov (United States)

    Yue, Shuai; Sun, Xiaoting; Wang, Ning; Wang, Yaning; Wang, Yue; Xu, Zhangrun; Chen, Mingli; Wang, Jianhua

    2017-11-15

    A surface-enhanced Raman scattering (SERS)-fluorescence dual-mode pH-sensing method based on Janus microgels was developed, which combined the advantages of high specificity offered by SERS and fast imaging afforded by fluorescence. Dual-mode probes, pH-dependent 4-mercaptobenzoic acid, and carbon dots were individually encapsulated in the independent hemispheres of Janus microparticles fabricated via a centrifugal microfluidic chip. On the basis of the obvious volumetric change of hydrogels in different pHs, the Janus microparticles were successfully applied for sensitive and reliable pH measurement from 1.0 to 8.0, and the two hemispheres showed no obvious interference. The proposed method addressed the limitation that sole use of the SERS-based pH sensing usually failed in strong acidic media. The gastric juice pH and extracellular pH change were measured separately in vitro using the Janus microparticles, which confirmed the validity of microgels for pH sensing. The microparticles exhibited good stability, reversibility, biocompatibility, and ideal semipermeability for avoiding protein contamination, and they have the potential to be implantable sensors to continuously monitor pH in vivo.

  8. A dual-mode 6-9 GHz transmitter for OFDM-UWB

    International Nuclear Information System (INIS)

    Chen Yunfeng; Gao Ting; Li Wei; Li Ning; Ren Junyan

    2011-01-01

    This paper presents a fully integrated dual-mode 6 to 9 GHz transmitter for both WiMedia and China MB-OFDM UWB applications. The proposed transmitter consists of a dual-mode I/QLPF, an up-conversion mixer, a two-stage power driver amplifier and a broadband high-speed frequency divider with LO buffers for I/Q LO carrier generation. The measurement results show that the gain ripple of the transmitter is within ±1.5/±2.8 dB from 6 to 8.7/9 GHz. The output IP3 is about +13.2 dBm, the output 1dBCP is around +2.8 dBm, and the LO leakage/sideband rejection ratio is about -35/-38 dBc. The ESD protected chip is fabricated with a TSMC 0.13 μm RFCMOS process with a die size of 1.6 x 1.3 mm 2 and the core circuit consumes only 46 mA under a 1.2 V supply. (semiconductor integrated circuits)

  9. A dual-mode 6-9 GHz transmitter for OFDM-UWB

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yunfeng; Gao Ting; Li Wei; Li Ning; Ren Junyan, E-mail: jyren@fudan.edu.cn, E-mail: w-li@fudan.edu.cn [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

    2011-05-15

    This paper presents a fully integrated dual-mode 6 to 9 GHz transmitter for both WiMedia and China MB-OFDM UWB applications. The proposed transmitter consists of a dual-mode I/QLPF, an up-conversion mixer, a two-stage power driver amplifier and a broadband high-speed frequency divider with LO buffers for I/Q LO carrier generation. The measurement results show that the gain ripple of the transmitter is within {+-}1.5/{+-}2.8 dB from 6 to 8.7/9 GHz. The output IP3 is about +13.2 dBm, the output 1dBCP is around +2.8 dBm, and the LO leakage/sideband rejection ratio is about -35/-38 dBc. The ESD protected chip is fabricated with a TSMC 0.13 {mu}m RFCMOS process with a die size of 1.6 x 1.3 mm{sup 2} and the core circuit consumes only 46 mA under a 1.2 V supply. (semiconductor integrated circuits)

  10. A Multifunctional Isolated and Non-Isolated Dual Mode Converter for Renewable Energy Conversion Applications

    Directory of Open Access Journals (Sweden)

    Yiwang Wang

    2017-11-01

    Full Text Available In this paper, a multifunctional isolated and non-isolated dual-mode low-power converter was designed for renewable energy conversion applications such as photovoltaic power generation to achieve different operating modes under bi-directional electrical conversion. The proposed topology consists of a bidirectional non-isolated DC/DC circuit and an isolated converter with a high-frequency transformer, which merge the advantages of both the conventional isolated converter and non-isolated converter with the combination of the two converter technologies. Compared with traditional converters, the multifunctional converter can not only realize conventional bi-directional functions, but can also be applied for many different operation modes and meet the high output/input ratio demands with the two converter circuits operating together. A novel control algorithm was proposed to achieve the various functions of the proposed converter. An experimental platform based on the proposed circuit was established. Both the simulation and experimental results indicated that the proposed converter could provide isolated and non-isolated modes in different applications, which could meet different practical engineering requirements.

  11. Study on using acetylene in dual fuel mode with exhaust gas recirculation

    International Nuclear Information System (INIS)

    Lakshmanan, T.; Nagarajan, G.

    2011-01-01

    Interest in employing gaseous fuels to internal combustion (IC) engines whether for stationary or mobile automotive applications has gained importance because of the economical, sustainable and environmental technical features associated with their usage. However, the incidence of preignition and knock remains a significant barrier in achieving their optimum performance potential. With the advent of latest technologies, the above barriers are eliminated. One such technique is timed manifold injection (TMI) of the gaseous fuel, which is controlled electronically to precisely monitor the induction of fuel to overcome the preignition problem in the intake. In the present investigation, acetylene was injected in the intake manifold in a single cylinder diesel engine, with a gas flow rate of 240 g/h, start of injection time is 10 o aTDC and 90 o CA (9.9 ms) duration, operated in dual fuel mode. In order to decrease the NOx emissions from acetylene-diesel engine, cooled EGR was employed. The cylinder pressure, brake thermal efficiency and emissions such as NOx, smoke, CO, HC, CO 2 and exhaust gas temperature were studied. Dual fuel operation with acetylene induction coupled with cooled EGR results in lowered NOx emissions and improved part load performance. -- Highlights: → Acetylene was tried in SI engines, but due to backfire further research was hindered as an alternative fuel. → But it is not tried in CI engine. Timed manifold injection was tried in diesel engine in the present work to combat backfire. → Author was successful in running the diesel engine in dual fuel mode. → 21% maximum diesel replacement was achieved. Author is confident that acetylene will be commercialised as a fuel for diesel engine in future.

  12. Modulating Brain Connectivity by Simultaneous Dual-Mode Stimulation over Bilateral Primary Motor Cortices in Subacute Stroke Patients

    Directory of Open Access Journals (Sweden)

    Jungsoo Lee

    2018-01-01

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS or transcranial direct current stimulation (tDCS has been used for the modulation of stroke patients’ motor function. Recently, more challenging approaches have been studied. In this study, simultaneous stimulation using both rTMS and tDCS (dual-mode stimulation over bilateral primary motor cortices (M1s was investigated to compare its modulatory effects with single rTMS stimulation over the ipsilesional M1 in subacute stroke patients. Twenty-four patients participated; 12 participants were assigned to the dual-mode stimulation group while the other 12 participants were assigned to the rTMS-only group. We assessed each patient’s motor function using the Fugl-Meyer assessment score and acquired their resting-state fMRI data at two times: prior to stimulation and 2 months after stimulation. Twelve healthy subjects were also recruited as the control group. The interhemispheric connectivity of the contralesional M1, interhemispheric connectivity between bilateral hemispheres, and global efficiency of the motor network noticeably increased in the dual-mode stimulation group compared to the rTMS-only group. Contrary to the dual-mode stimulation group, there was no significant change in the rTMS-only group. These data suggested that simultaneous dual-mode stimulation contributed to the recovery of interhemispheric interaction than rTMS only in subacute stroke patients. This trial is registered with NCT03279640.

  13. Multilevel DC link inverter

    Science.gov (United States)

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  14. Design and implementation of a new modified sliding mode controller for grid-connected inverter to controlling the voltage and frequency.

    Science.gov (United States)

    Ghanbarian, Mohammad Mehdi; Nayeripour, Majid; Rajaei, Amirhossein; Mansouri, Mohammad Mahdi

    2016-03-01

    As the output power of a microgrid with renewable energy sources should be regulated based on the grid conditions, using robust controllers to share and balance the power in order to regulate the voltage and frequency of microgrid is critical. Therefore a proper control system is necessary for updating the reference signals and determining the proportion of each inverter in the microgrid control. This paper proposes a new adaptive method which is robust while the conditions are changing. This controller is based on a modified sliding mode controller which provides adapting conditions in linear and nonlinear loads. The performance of the proposed method is validated by representing the simulation results and experimental lab results. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Design and multifidelity analysis of dual mode scramjet compression system using coupled NPSS and fluent simulation

    Science.gov (United States)

    Vijayakumar, Nandakumar

    Hypersonic airbreathing engines mark a potential future development of the aerospace industry and immense efforts have been taken in gaining knowledge in them for the past decades. The physical phenomenon occurring at the hypersonic flow regime makes the design and performance prediction of a scramjet engine hard. Though cutting-edge simulation tools fight their way toward accurate prediction of the environment, the time consumed by the entire process in designing and analyzing a scramjet engine and its component may be exorbitant. A multi-fidelity approach for designing a scramjet with a cruising Mach number of 6 is detailed in this research where high-order simulations are applied according to the physics involved in the component. Two state-of-the-art simulation tools were used to take the aerodynamic and propulsion disciplines into account for realistic prediction of the individual components as well as the entire scramjet. The specific goal of this research is to create a virtual environment to design and analyze a hypersonic, two-dimensional, planar inlet and isolator to check its operability for a dual-mode scramjet engine. The dual mode scramjet engine starts at a Mach number of 3.5 where it operates as a ramjet and accelerates to Mach 6 to be operated as a scramjet engine. The intercomponent interaction between the compression components with the rest of the engine is studied by varying the fidelity of the numerical simulation according to the complexity of the situation. Efforts have been taken to track the transition Mach number as it switches from ramjet to scramjet. A complete scramjet assembly was built using the Numerical Propulsion Simulation System (NPSS) and the performance of the engine was evaluated for various scenarios. Different numerical techniques were opted for varying the fidelity of the analysis with the highest fidelity consisting of 2D RANS CFD simulation. The interaction between the NPSS elements with the CFD solver is governed by the

  16. Dual mode antibacterial activity of ion substituted calcium phosphate nanocarriers for bone infections

    Directory of Open Access Journals (Sweden)

    Sampath Kumar eT.S.

    2015-05-01

    Full Text Available Nanotechnology has tremendous potential for the management of infectious diseases caused by multi-drug resistant (MDR bacteria, through the development of newer antibacterial materials and efficient modes of antibiotic delivery. Calcium phosphate (CaP bioceramics are commonly used as bone substitutes due to their similarity to bone mineral and are widely researched upon for the treatment of bone infections associated with bone loss. CaPs can be used as local antibiotic delivery agents for bone infections and can be substituted with antibacterial ions in their crystal structure to have a wide spectrum, sustained antibacterial activity even against drug resistant bacteria. In the present work, a dual mode antibiotic delivery system with antibacterial ion substituted calcium deficient hydroxyapatite (CDHA nanoparticles has been developed. Antibacterial ions such as zinc, silver and strontium have been incorporated into CDHA at concentrations of 6 at. %, 0.25-0.75 at. % and 2.5-7.5 at. % respectively. The samples were found to be phase pure, acicular nanoparticles of length 40-50 nm and width 5-6 nm approximately. The loading and release profile of doxycycline, a commonly used antibiotic, was studied from the nanocarriers. The drug release was studied for five days and the release profile was influenced by the ion concentrations. The release of antibacterial ions was studied over a period of 21 days. The ion substituted CDHA samples were tested for antibacterial efficacy on S.aureus and E.coli by MIC/MBC studies and time-kill assay. AgCDHA and ZnCDHA showed high antibacterial activity against both bacteria while SrCDHA was weakly active against S.aureus. Present study shows that the antibiotic release can provide the initial high antibacterial activity and the sustained ion release can provide a long-term antibacterial activity. Such dual mode antibiotic and antibacterial ion release offers an efficient and potent way to treat an incumbent drug

  17. Unprecedented large inverted repeats at the replication terminus of circular bacterial chromosomes suggest a novel mode of chromosome rescue

    Science.gov (United States)

    El Kafsi, Hela; Loux, Valentin; Mariadassou, Mahendra; Blin, Camille; Chiapello, Hélène; Abraham, Anne-Laure; Maguin, Emmanuelle; van de Guchte, Maarten

    2017-01-01

    The first Lactobacillus delbrueckii ssp. bulgaricus genome sequence revealed the presence of a very large inverted repeat (IR), a DNA sequence arrangement which thus far seemed inconceivable in a non-manipulated circular bacterial chromosome, at the replication terminus. This intriguing observation prompted us to investigate if similar IRs could be found in other bacteria. IRs with sizes varying from 38 to 76 kbp were found at the replication terminus of all 5 L. delbrueckii ssp. bulgaricus chromosomes analysed, but in none of 1373 other chromosomes. They represent the first naturally occurring very large IRs detected in circular bacterial genomes. A comparison of the L. bulgaricus replication terminus regions and the corresponding regions without IR in 5 L. delbrueckii ssp. lactis genomes leads us to propose a model for the formation and evolution of the IRs. The DNA sequence data are consistent with a novel model of chromosome rescue after premature replication termination or irreversible chromosome damage near the replication terminus, involving mechanisms analogous to those proposed in the formation of very large IRs in human cancer cells. We postulate that the L. delbrueckii ssp. bulgaricus-specific IRs in different strains derive from a single ancestral IR of at least 93 kbp. PMID:28281695

  18. Inverted oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Yuce, C [Physics Department, Anadolu University, Eskisehir (Turkey); Kilic, A [Physics Department, Anadolu University, Eskisehir (Turkey); Coruh, A [Physics Department, Sakarya University, Sakarya (Turkey)

    2006-07-15

    The inverted harmonic oscillator problem is investigated quantum mechanically. The exact wavefunction for the confined inverted oscillator is obtained and it is shown that the associated energy eigenvalues are discrete, and the energy is given as a linear function of the quantum number n.

  19. Dual fuel mode operation in diesel engines using renewable fuels: Rubber seed oil and coir-pith producer gas

    Energy Technology Data Exchange (ETDEWEB)

    Ramadhas, A.S.; Jayaraj, S.; Muraleedharan, C. [Department of Mechanical Engineering, National Institute of Technology Calicut, Calicut-673601 (India)

    2008-09-15

    Partial combustion of biomass in the gasifier generates producer gas that can be used as supplementary or sole fuel for internal combustion engines. Dual fuel mode operation using coir-pith derived producer gas and rubber seed oil as pilot fuel was analyzed for various producer gas-air flow ratios and at different load conditions. The engine is experimentally optimized with respect to maximum pilot fuel savings in the dual fuel mode operation. The performance and emission characteristics of the dual fuel engine are compared with that of diesel engine at different load conditions. Specific energy consumption in the dual-fuel mode of operation with oil-coir-pith operation is found to be in the higher side at all load conditions. Exhaust emission was found to be higher in the case of dual fuel mode of operation as compared to neat diesel/oil operation. Engine performance characteristics are inferior in fully renewable fueled engine operation but it suitable for stationary engine application, particularly power generation. (author)

  20. Dual mode operation, highly selective nanohole array-based plasmonic colour filters

    Science.gov (United States)

    Fouladi Mahani, Fatemeh; Mokhtari, Arash; Mehran, Mahdiyeh

    2017-09-01

    Taking advantage of nanostructured metal films as plasmonic colour filters (PCFs) has been evolved remarkably as an alternative to the conventional technologies of chemical colour filtering. However, most of the proposed PCFs depict a poor colour purity focusing on generating either the additive or subtractive colours. In this paper, we present dual mode operation PCFs employing an opaque aluminium film patterned with sub-wavelength holes. Subtractive colours like cyan, magenta, and yellow are the results of reflection mode of these filters yielding optical efficiencies as high as 70%-80% and full width at half maximum of the stop-bands up to 40-50 nm. The colour selectivity of the transmission mode for the additive colours is also significant due to their enhanced performance through the utilization of a relatively thick aluminium film in contact with a modified dielectric environment. These filters provide a simple design with one-step lithography in addition to compatibility with the conventional CMOS processes. Moreover, they are polarization insensitive due to their symmetric geometry. A complete palette of pure subtractive and additive colours has been realized with potential applications, such as multispectral imaging, CMOS image sensors, displays, and colour printing.

  1. A dose-per-pulse monitor for a dual-mode medical accelerator

    International Nuclear Information System (INIS)

    Galbraith, D.M.; Martell, E.S.; Fueurstake, T.; Norrlinger, B.; Schwendener, H.; Rawlinson, J.A.

    1990-01-01

    On a radiotherapy accelerator, the dose monitoring system is the last level of protection between the patient and the extremely high dose rate which all accelerators are capable of producing. The risk of losing this level of protection is substantially reduced if two or more dose monitoring systems are used which are mechanically and electrically independent in design. This paper describes the installation of an independent radiation monitor in a dual-mode, computer-controlled accelerator with a moveable monitor chamber. The added device is fixed in the beam path, is capable of monitoring each beam pulse, and is capable of terminating irradiation within the pulse repetition period if any measured pulse is unacceptably high

  2. Dual-mode gradient HPLC procedure for the simultaneous determination of chloroquine and proguanil.

    Science.gov (United States)

    Paci, A; Caire-Maurisier, A-M; Rieutord, A; Brion, F; Clair, P

    2002-01-01

    In order to assay the antipaludic capsule of the Service de Santé des Armées (SSA), that contains two antimalarial drugs, i.e. chloroquine sulfate (CQS, cp1) and proguanil hydrochloride (PGH, cp5), a HPLC procedure was developed. A reversed-phase ion-pair high-performance liquid chromatography (HPLC) method with an ultraviolet detection at 254 nm was set up and validated. Elution system includes programming of both organic concentration and flow-rate known as 'dual-mode gradient'. This method allows the simultaneous determination of both active compounds and separation of four process related substances. The method is simple, rapid, selective and accurate, and the precision is good with an inter- and intra-assay of <2%. The sensitivity is particularly suitable for pharmaceutical quality control.

  3. 10 KWe dual-mode space nuclear power system for military and scientific applications

    International Nuclear Information System (INIS)

    Malloy, J.; Westerman, K.; Rochow, R.; Scoles, S.

    1992-01-01

    This paper discusses a 10 KWe dual-mode space power system concept which has been identified and is based on INEL's Small Externally-fueled Heat Pipe Thermionic Reactor (SEHPTR) concept. This power system will enhance user capabilities by providing reliable electric power and by providing two propulsion systems; electric power for an arc-jet electric propulsion system and direct thrust by heating hydrogen propellant inside the reactor. The low thrust electric thrusters allow efficient station keeping and long-term maneuvering. This paper will focus on the nuclear power system design, including: the reactor with its UO 2 fuel in tungsten clad, 36 thermionic heat pipe modules (THPMs) which produce electricity within the reactor and remove waste heat, radiation shielding, waste heat radiators, and reactivity control systems. The use of non-vented fuel elements for short lifetime missions (under five years) will be described

  4. Monitoring and guidance of HIFU beams with dual-mode ultrasound arrays.

    Science.gov (United States)

    Ballard, John R; Casper, Andrew J; Ebbini, Emad S

    2009-01-01

    We present experimental results illustrating the unique advantages of dual-mode array (DMUA) systems in monitoring and guidance of high intensity focused ultrasound (HIFU) lesion formation. DMUAs offer a unique paradigm in image-guided surgery; one in which images obtained using the same therapeutic transducer provide feedback for: 1) refocusing the array in the presence of strongly scattering objects, e.g. the ribs, 2) temperature change at the intended location of the HIFU focus, and 3) changes in the echogenicity of the tissue in response to therapeutic HIFU. These forms of feedback have been demonstrated in vitro in preparation for the design and implementation of a real-time system for imaging and therapy with DMUAs. The results clearly demonstrate that DMUA image feedback is spatially accurate and provide sufficient spatial and contrast resolution for identification of high contrast objects like the ribs and significant blood vessels in the path of the HIFU beam.

  5. Dual-mode nested search method for categorical uncertain multi-objective optimization

    Science.gov (United States)

    Tang, Long; Wang, Hu

    2016-10-01

    Categorical multi-objective optimization is an important issue involved in many matching design problems. Non-numerical variables and their uncertainty are the major challenges of such optimizations. Therefore, this article proposes a dual-mode nested search (DMNS) method. In the outer layer, kriging metamodels are established using standard regular simplex mapping (SRSM) from categorical candidates to numerical values. Assisted by the metamodels, a k-cluster-based intelligent sampling strategy is developed to search Pareto frontier points. The inner layer uses an interval number method to model the uncertainty of categorical candidates. To improve the efficiency, a multi-feature convergent optimization via most-promising-area stochastic search (MFCOMPASS) is proposed to determine the bounds of objectives. Finally, typical numerical examples are employed to demonstrate the effectiveness of the proposed DMNS method.

  6. Yb3+,Er3+,Eu3+-codoped YVO4 material for bioimaging with dual mode excitation

    International Nuclear Information System (INIS)

    Thao, Chu Thi Bich; Huy, Bui The; Sharipov, Mirkomil; Kim, Jin-Ik.; Dao, Van-Duong; Moon, Ja-Young; Lee, Yong-Ill

    2017-01-01

    We propose an efficient bioimaging strategy using Yb 3+ ,Er 3+ ,Eu 3+ -triplet doped YVO 4 nanoparticles which were synthesized with polymer as a template. The obtained particles possess nanoscale, uniform, and flexible excitation. The effect of Eu 3+ ions on the luminescence properties of YVO 4 :Yb 3+ ,Er 3+ ,Eu 3+ was investigated. The upconversion mechanism of the prepared material was also discussed. The structure and optical properties of the prepared material were characterized by using X-ray diffraction (XRD), Fourier-transform IR spectroscopy (FTIR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM) upconversion and photoluminescence spectra. The Commission International de I′Eclairage (CIE) chromaticity coordinates was investigated to confirm the performance of color luminescent emission. The prepared YVO 4 :Yb 3+ ,Er 3+ ,Eu 3+ nanoparticles could be easily dispersed in water by surface modification with cysteine (Cys) and glutathione (GSH). The aqueous dispersion of the modified YVO 4 :Yb 3+ ,Er 3+ ,Eu 3+ exhibits bright upconversion and downconversion luminescence and has been applied for bioimaging of HeLa cells. Our developed material with dual excitation offers a promising advance in bioimaging. - Highlights: • Prepared particles possess nanoscale size, uniform, and larger scale. • The material exhibits strong emission under dual mode excitations. • The surface material has been applied for bioimaging of HeLa cell. • Low cytotoxicity, no auto-fluorescence

  7. The effects of voice and manual control mode on dual task performance

    Science.gov (United States)

    Wickens, C. D.; Zenyuh, J.; Culp, V.; Marshak, W.

    1986-01-01

    Two fundamental principles of human performance, compatibility and resource competition, are combined with two structural dichotomies in the human information processing system, manual versus voice output, and left versus right cerebral hemisphere, in order to predict the optimum combination of voice and manual control with either hand, for time-sharing performance of a dicrete and continuous task. Eight right handed male subjected performed a discrete first-order tracking task, time-shared with an auditorily presented Sternberg Memory Search Task. Each task could be controlled by voice, or by the left or right hand, in all possible combinations except for a dual voice mode. When performance was analyzed in terms of a dual-task decrement from single task control conditions, the following variables influenced time-sharing efficiency in diminishing order of magnitude, (1) the modality of control, (discrete manual control of tracking was superior to discrete voice control of tracking and the converse was true with the memory search task), (2) response competition, (performance was degraded when both tasks were responded manually), (3) hemispheric competition, (performance degraded whenever two tasks were controlled by the left hemisphere) (i.e., voice or right handed control). The results confirm the value of predictive models invoice control implementation.

  8. Experimental study on combustion modes and thrust performance of a staged-combustor of the scramjet with dual-strut

    Science.gov (United States)

    Yang, Qingchun; Chetehouna, Khaled; Gascoin, Nicolas; Bao, Wen

    2016-05-01

    To enable the scramjet operate in a wider flight Mach number, a staged-combustor with dual-strut is introduced to hold more heat release at low flight Mach conditions. The behavior of mode transition was examined using a direct-connect model scramjet experiment along with pressure measurements. The typical operating modes of the staged-combustor are analyzed. Fuel injection scheme has a significant effect on the combustor operating modes, particularly for the supersonic combustion mode. Thrust performances of the combustor with different combustion modes and fuel distributions are reported in this paper. The first-staged strut injection has a better engine performance in the operation of subsonic combustion mode. On the contrast, the second-staged strut injection has a better engine performance in the operation of supersonic combustion mode.

  9. Dual-mode, high energy utilization system concept for mars missions

    International Nuclear Information System (INIS)

    El-Genk, Mohamed S.

    2000-01-01

    This paper describes a dual-mode, high energy utilization system concept based on the Pellet Bed Reactor (PeBR) to support future manned missions to Mars. The system uses proven Closed Brayton Cycle (CBC) engines to partially convert the reactor thermal power to electricity. The electric power generated is kept the same during the propulsion and the power modes, but the reactor thermal power in the former could be several times higher, while maintaining the reactor temperatures almost constant. During the propulsion mode, the electric power of the system, minus ∼1-5 kW e for house keeping, is used to operate a Variable Specific Impulse Magnetoplasma Rocket (VASIMR). In addition, the reactor thermal power, plus more than 85% of the head load of the CBC engine radiators, are used to heat hydrogen. The hot hydrogen is mixed with the high temperature plasma in a VASIMR to provide both high thrust and I sp >35,000 N.s/kg, reducing the travel time to Mars to about 3 months. The electric power also supports surface exploration of Mars. The fuel temperature and the inlet temperatures of the He-Xe working fluid to the nuclear reactor core and the CBC turbine are maintained almost constant during both the propulsion and power modes to minimize thermal stresses. Also, the exit temperature of the He-Xe from the reactor core is kept at least 200 K below the maximum fuel design temperature. The present system has no single point failure and could be tested fully assembled in a ground facility using electric heaters in place of the nuclear reactor. Operation and design parameters of a 40-kW e prototype are presented and discussed to illustrate the operation and design principles of the proposed system

  10. A novel detector based on dual-mode fiber polished half block's characteristics for sensitive monitorings of radiation and materials

    International Nuclear Information System (INIS)

    Saeed, Ghadirli

    2005-01-01

    Full text : The overlay index dependence characteristics of the power distribution between two modes of dual-mode fiber polished half blocks is studied. The heat dependence characteristics of a certain overlay index affects the modal power distributions at the input of interferometer sensors used for monitoring the sensitive heat radiation changes. The other fundamental applications such as material recognitions through the index dependence characteristics in the closed chambers is also suggested

  11. Investigation on utilization of biogas and Karanja oil biodiesel in dual fuel mode in a single cylinder DI diesel engine

    Energy Technology Data Exchange (ETDEWEB)

    Prasanna Pattanaik, Bhabani; Nayak, Chandrakanta [Department of Mechanical Eng., Gandhi Institute for Technological Advancement, Madanpur, Bhubaneswar - 752054, Odisha (India); Kumar Nanda, Basanta [Department of Mechanical Eng., Maharaja Institute of Technology, Bhubaneswar, Odisha (India)

    2013-07-01

    In this work, experiments were performed on a single cylinder DI diesel engine by using bio-gas as a primary fuel and Karanja oil biodiesel and diesel oil as secondary fuels in dual fuel operation. The experiments were performed to measure performance parameters i.e. (brake specific fuel consumption, brake thermal efficiency and exhaust gas temperature) and emission parameters such as carbon monoxide, carbon dioxide, nitrogen oxide unburned hydro carbon and smoke etc. at different load conditions. For the dual-fuel system, the intake system of the test engine was modified to convert into biogas and biodiesel of a dual-fueled combustion engine. Biogas was injected during the intake process by gas injectors. The study showed that, the engine performance parameters like BP, BTE and EGT gradually increase with increase in engine load for all test conditions using both pilot fuels diesel and KOBD. However, the BSFC of the engine showed decreasing slope with increase in engine load for all test conditions. Above 40% engine load the BSFC values for all test fuels are very close to each other. The engine emission analysis showed that the CO2, CO and NOx emissions increase with increase in engine load for both single and dual fuel mode operation using both pilot fuels. The NOx concentration of exhaust gases in dual fuel mode is superior than that of single mode.

  12. Fatigue Failure Modes of the Grain Size Transition Zone in a Dual Microstructure Disk

    Science.gov (United States)

    Gabb, Timothy P.; Kantzos, Pete T.; Palsa, Bonnie; Telesman, Jack; Gayda, John; Sudbrack, Chantal K.

    2012-01-01

    Mechanical property requirements vary with location in nickel-based superalloy disks. In order to maximize the associated mechanical properties, heat treatment methods have been developed for producing tailored grain microstructures. In this study, fatigue failure modes of a grain size transition zone in a dual microstructure disk were evaluated. A specialized heat treatment method was applied to produce varying grain microstructure in the bore to rim portions of a powder metallurgy processed nickel-based superalloy disk. The transition in grain size was concentrated in a zone of the disk web, between the bore and rim. Specimens were extracted parallel and transversely across this transition zone, and multiple fatigue tests were performed at 427 C and 704 C. Grain size distributions were characterized in the specimens, and related to operative failure initiation modes. Mean fatigue life decreased with increasing maximum grain size, going out through the transition zone. The scatter in limited tests of replicates was comparable for failures of uniform gage specimens in all transition zone locations examined.

  13. A tunable and switchable single-longitudinal-mode dual-wavelength fiber laser with a simple linear cavity.

    Science.gov (United States)

    He, Xiaoying; Fang, Xia; Liao, Changrui; Wang, D N; Sun, Junqiang

    2009-11-23

    A simple linear cavity erbium-doped fiber laser based on a Fabry-Perot filter which consists of a pair of fiber Bragg gratings is proposed for tunable and switchable single-longitudinal-mode dual-wavelength operation. The single-longitudinal-mode is obtained by the saturable absorption of an unpumed erbium-doped fiber together with a narrow-band fiber Bragg grating. Under the high pump power (>166 mW) condition, the stable dual-wavelength oscillation with uniform amplitude can be realized by carefully adjusting the polarization controller in the cavity. Wavelength selection and switching are achieved by tuning the narrow-band fiber Bragg grating in the system. The spacing of the dual-wavelength can be selected at 0.20 nm (approximately 25.62 GHz), 0.22 nm (approximately 28.19 GHz) and 0.54 nm (approximately 69.19 GHz).

  14. Vibrational correlation between conjugated carbonyl and diazo modes studied by single- and dual-frequency two-dimensional infrared spectroscopy

    International Nuclear Information System (INIS)

    Maekawa, Hiroaki; Sul, Soohwan; Ge, Nien-Hui

    2013-01-01

    Highlights: ► Vibrational dynamics of conjugated C=O and N=N modes of ethyl diazoacetate was studied. ► Their frequency–frequency correlation functions are different. ► The dual-frequency 2D IR spectrum indicates anticorrelated frequency fluctuations. ► Correlation effects on dual-frequency 2D IR spectra are discussed. ► The existence of cis and trans conformers is revealed in 2D IR spectra. - Abstract: We have applied infrared three-pulse photon echo and single- and dual-frequency 2D IR spectroscopy to the ester C=O and diazo N=N stretching modes in ethyl diazoacetate (EDA), and investigated their vibrational frequency fluctuations and correlation. The two modes exhibit different vibrational dynamics and 2D lineshape, which are well simulated by frequency–frequency correlation functions (FFCFs) with two decaying components. Although the FT IR spectrum shows a single C=O band, absolute magnitude 2D IR nonrephasing spectrum displays spectral signatures supporting the presence of cis and trans conformations. The cross-peak inclined toward the anti-diagonal in the dual-frequency 2D IR spectrum, indicating that the frequency fluctuations of the two modes are anticorrelated. This behavior is attributed to anticorrelated change in the bond orders when solvent and structural fluctuations causes EDA to adopt a different mixture of the two dominant resonance structures. The effects of cross FFCF on the cross-peak line shape are discussed

  15. Vibrational correlation between conjugated carbonyl and diazo modes studied by single- and dual-frequency two-dimensional infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Hiroaki; Sul, Soohwan [Department of Chemistry, University of California at Irvine, Irvine, CA 92697-2025 (United States); Ge, Nien-Hui, E-mail: nhge@uci.edu [Department of Chemistry, University of California at Irvine, Irvine, CA 92697-2025 (United States)

    2013-08-30

    Highlights: ► Vibrational dynamics of conjugated C=O and N=N modes of ethyl diazoacetate was studied. ► Their frequency–frequency correlation functions are different. ► The dual-frequency 2D IR spectrum indicates anticorrelated frequency fluctuations. ► Correlation effects on dual-frequency 2D IR spectra are discussed. ► The existence of cis and trans conformers is revealed in 2D IR spectra. - Abstract: We have applied infrared three-pulse photon echo and single- and dual-frequency 2D IR spectroscopy to the ester C=O and diazo N=N stretching modes in ethyl diazoacetate (EDA), and investigated their vibrational frequency fluctuations and correlation. The two modes exhibit different vibrational dynamics and 2D lineshape, which are well simulated by frequency–frequency correlation functions (FFCFs) with two decaying components. Although the FT IR spectrum shows a single C=O band, absolute magnitude 2D IR nonrephasing spectrum displays spectral signatures supporting the presence of cis and trans conformations. The cross-peak inclined toward the anti-diagonal in the dual-frequency 2D IR spectrum, indicating that the frequency fluctuations of the two modes are anticorrelated. This behavior is attributed to anticorrelated change in the bond orders when solvent and structural fluctuations causes EDA to adopt a different mixture of the two dominant resonance structures. The effects of cross FFCF on the cross-peak line shape are discussed.

  16. Dual wavelength Mode-Locking of InAs/InP quantum dot laser diodes at 1.5µm

    NARCIS (Netherlands)

    Tahvili, M.S.; Heck, M.J.R.; Nötzel, R.; Smit, M.K.; Bente, E.A.J.M.

    2011-01-01

    We report on stable dual-wavelength mode-locking of 3.1GHz and 10GHz two-section InAs/InP(100) quantum dot laser diodes. Evaluation of relative time delay between different spectral components indicates opposite sign of chirp over the two spectral lobes

  17. Tunable and switchable dual-wavelength passively mode-locked Bi-doped all-fiber ring laser based on nonlinear polarization rotation

    International Nuclear Information System (INIS)

    Luo, A-P; Luo, Z-C; Xu, W-C; Dvoyrin, V V; Mashinsky, V M; Dianov, E M

    2011-01-01

    We demonstrate a tunable and switchable dual-wavelength passively mode-locked Bi-doped all-fiber ring laser by using nonlinear polarization rotation (NPR) technique. Exploiting the spectral filtering effect caused by the combination of the polarizer and intracavity birefringence, the wavelength separation of dual-wavelength mode-locked pulses can be flexibly tuned between 2.38 and 20.45 nm. Taking the advantage of NPR-induced intensity-dependent loss to suppress the mode competition, the stable dual-wavelength pulses output is obtained at room temperature. Moreover, the dual-wavelength switchable operation is achieved by simply rotating the polarization controllers (PCs)

  18. Real-time dual-comb spectroscopy with a free-running bidirectionally mode-locked fiber laser

    Science.gov (United States)

    Mehravar, S.; Norwood, R. A.; Peyghambarian, N.; Kieu, K.

    2016-06-01

    Dual-comb technique has enabled exciting applications in high resolution spectroscopy, precision distance measurements, and 3D imaging. Major advantages over traditional methods can be achieved with dual-comb technique. For example, dual-comb spectroscopy provides orders of magnitude improvement in acquisition speed over standard Fourier-transform spectroscopy while still preserving the high resolution capability. Wider adoption of the technique has, however, been hindered by the need for complex and expensive ultrafast laser systems. Here, we present a simple and robust dual-comb system that employs a free-running bidirectionally mode-locked fiber laser operating at telecommunication wavelength. Two femtosecond frequency combs (with a small difference in repetition rates) are generated from a single laser cavity to ensure mutual coherent properties and common noise cancellation. As the result, we have achieved real-time absorption spectroscopy measurements without the need for complex servo locking with accurate frequency referencing, and relatively high signal-to-noise ratio.

  19. Dual-mode ferromagnetic resonance in an FeCoB/Ru/FeCoB synthetic antiferromagnet with uniaxial anisotropy

    Science.gov (United States)

    Wang, Cuiling; Zhang, Shouheng; Qiao, Shizhu; Du, Honglei; Liu, Xiaomin; Sun, Ruicong; Chu, Xian-Ming; Miao, Guo-Xing; Dai, Youyong; Kang, Shishou; Yan, Shishen; Li, Shandong

    2018-05-01

    Dual-mode ferromagnetic resonance is observed in FeCoB/Ru/FeCoB trilayer synthetic antiferromagnets with uniaxial in-plane magnetic anisotropy. The optical mode is present in the (0-108 Oe) magnetic field range, where the top and bottom layer magnetizations are aligned in opposite directions. The strong acoustic mode appears, when the magnetic field exceeds the 300 Oe value, which corresponds to the flop transition in the trilayer. Magnetic field and angular dependences of resonant frequencies are studied for both optical (low-field) and acoustic (high field) modes. The low-field mode is found to be anisotropic but insensitive to the magnetic field value. In contrast, the high field mode is quasi-isotropic, but its resonant frequency is tunable by the value of the magnetic field. The coexistence of two modes of ferromagnetic resonance as well as switching between them with the increase in the magnetic field originates from the difference in the sign of interlayer coupling energy at the parallel and antiparallel configurations of the synthetic antiferromagnet. The dual-mode resonance in the studied trilayer structures provides greater flexibility in the design and functionalization of micro-inductors in monolithic microwave integrated circuits.

  20. Radio frequency ablation in the rabbit lung using wet electrodes: comparison of monopolar and dual bipolar electrode mode

    International Nuclear Information System (INIS)

    Jin, Gong Yong; Park, Sang Hee; Han, Young Min; Chung, Gyung Ho; Kwak, Hyo Sung; Jeon, Soo Bin; Lee, Yong Chul

    2006-01-01

    To compare the effect of radio frequency ablation (RFA) on the dimensions of radio frequency coagulation necrosis in a rabbit lung using a wet electrode in monopolar mode with that in dual electrode bipolar mode at different infusion rates (15 mm/hr versus 30 ml/hr) and saline concentrations (0.9% normal versus 5.8% hypertonic saline. Fifty ablation zones (one ablation zone in each rabbit) were produced in 50 rabbit using one or two 16-guage wet electrodes with a 1- cm active tip. The RFA system used in the monopolar and dual electrode wet bipolar RFA consisted of a 375-kHz generator (Elektrotom HiTT 106, Berchtold, Medizinelektronik, Germany). The power used was 30 watts and the exposure time was 5 minutes. The rabbits were assigned to one of five groups. Group A (n = 10) was infused with 0.9% NaCl used at a rate of 30 ml/hr in a monopolar mode. Groups B (n=10) and C (n=10) were infused with 0.9% NaCl at a rate of 15 and 30ml/hr, respectively in dual electrode bipolar mode; groups D (n=10) and E (n=10) were infused with 5.8% NaCl at a rate of 15 and 30 ml/hr, respectively in a dual electrode bipolar mode. The dimensions of the ablation zones in the gross specimens from the groups were compared using one-way analysis of variance by means of the Scheffe test (post-hoc testing). The mean largest diameter of the ablation zones was larger in dual electrode bipolar mode (30.9 ± 4.4 mm) than in monopolar mode (22.5 ± 3.5 mm). The mean smallest diameter of the ablation zones was larger in dual electrode bipolar mode (22.3 ± 2.5 mm) than in monopolar mode (19.5 ± 3.5 mm). There were significant differences in the largest and smallest dimension between the monopolar (group A ) ana dual electrode wet bipolar mode (groups B-E). In dual electrode bipolar mode, the mean largest diameter of the ablation zones was larger at an infusion rate of 15 ml/hr (34.2 ± 4.0 mm) than at 30 ml/hr (27.6 ± 0.0 mm), and the mean smallest diameter of the ablation zones was larger at an

  1. Probing the fundamental limit of niobium in high radiofrequency fields by dual mode excitation in superconducting radiofrequency cavities

    International Nuclear Information System (INIS)

    Eremeev, Grigory; Geng, Rongli; Palczewski, Ari

    2011-01-01

    We have studied thermal breakdown in several multicell superconducting radiofrequency cavity by simultaneous excitation of two TM 010 passband modes. Unlike measurements done in the past, which indicated a clear thermal nature of the breakdown, our measurements present a more complex picture with interplay of both thermal and magnetic effects. JLab LG-1 that we studied was limited at 40.5 MV/m, corresponding to B peak = 173 mT, in 89 mode. Dual mode measurements on this quench indicate that this quench is not purely magnetic, and so we conclude that this field is not the fundamental limit in SRF cavities

  2. Tunable and stable single-longitudinal-mode dual-wavelength erbium fiber laser with 1.3 nm mode spacing output

    International Nuclear Information System (INIS)

    Yeh, C H; Shih, F Y; Wang, C H; Chow, C W; Chi, S

    2008-01-01

    In this investigation, we propose and investigate a stable and tunable dual-wavelength erbium-doped fiber (EDF) ring laser with self-injected Fabry-Perot laser diode (FP-LD) scheme. By using an FP-LD incorporated with a tunable bandpass filter (TBF) within the gain cavity, the fiber laser can lase at two single-longitudinal-mode (SLM) wavelengths simultaneously due to the self-injected operation. The proposed dual-wavelength laser has a good performance of the output power and optical side-mode suppression ratio (SMSR). The laser also shows a wide tuning range from 1523.08 to 1562.26 nm. Besides, the output stabilities of the fiber laser are also discussed

  3. High-efficiency dual-modes vortex beam generator with polarization-dependent transmission and reflection properties.

    Science.gov (United States)

    Tang, Shiwei; Cai, Tong; Wang, Guang-Ming; Liang, Jian-Gang; Li, Xike; Yu, Jiancheng

    2018-04-23

    Vortex beam is believed to be an effective way to extend communication capacity, but available efforts suffer from the issues of complex configurations, fixed operation mode as well as low efficiency. Here, we propose a general strategy to design dual-modes vortex beam generator by using metasurfaces with polarization-dependent transmission and reflection properties. Combining the focusing and vortex functionalities, we design/fabricate a type of compact dual-modes vortex beam generator operating at both reflection/transmission sides of the system. Experimental results demonstrate that the designed metadevice can switch freely and independently between the reflective vortex with topological charge m 1  = 2 and transmissive vortex with m 2  = 1. Moreover, the metadevice exhibits very high efficiencies of 91% and 85% for the reflective and transmissive case respectively. Our findings open a door for multifunctional metadevices with high performances, which indicate wide applications in modern integration-optics and wireless communication systems.

  4. A dual-mode operation overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic mode output

    Science.gov (United States)

    Bai, Zhen; Zhang, Jun; Zhong, Huihuang

    2016-04-01

    An overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic (TEM) mode output is designed and presented, by using a kind of coaxial slow wave structure (SWS) with large transversal dimension and small distance between inner and outer conductors. The generator works in dual-mode operation mechanism. The electron beam synchronously interacts with 7π/8 mode of quasi-TEM, at the meanwhile exchanges energy with 3π/8 mode of TM01. The existence of TM01 mode, which is traveling wave, not only increases the beam-wave interaction efficiency but also improves the extraction efficiency. The large transversal dimension of coaxial SWS makes its power capacity higher than that of other reported millimeter-wave devices and the small distance between inner and outer conductors allows only two azimuthally symmetric modes to coexist. The converter after the SWS guarantees the mode purity of output power. Particle-in-cell simulation shows that when the diode voltage is 400 kV and beam current is 3.8 kA, the generation of microwave at 32.26 GHz with an output power of 611 MW and a conversion efficiency of 40% is obtained. The power percentage carried by TEM mode reaches 99.7% in the output power.

  5. A dual-mode operation overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic mode output

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Zhen; Zhang, Jun, E-mail: zhangjun@nudt.edu.cn; Zhong, Huihuang [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2016-04-15

    An overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic (TEM) mode output is designed and presented, by using a kind of coaxial slow wave structure (SWS) with large transversal dimension and small distance between inner and outer conductors. The generator works in dual-mode operation mechanism. The electron beam synchronously interacts with 7π/8 mode of quasi-TEM, at the meanwhile exchanges energy with 3π/8 mode of TM{sub 01}. The existence of TM{sub 01} mode, which is traveling wave, not only increases the beam-wave interaction efficiency but also improves the extraction efficiency. The large transversal dimension of coaxial SWS makes its power capacity higher than that of other reported millimeter-wave devices and the small distance between inner and outer conductors allows only two azimuthally symmetric modes to coexist. The converter after the SWS guarantees the mode purity of output power. Particle-in-cell simulation shows that when the diode voltage is 400 kV and beam current is 3.8 kA, the generation of microwave at 32.26 GHz with an output power of 611 MW and a conversion efficiency of 40% is obtained. The power percentage carried by TEM mode reaches 99.7% in the output power.

  6. Unidirectional, dual-comb lasing under multiple pulse formation mechanisms in a passively mode-locked fiber ring laser

    Science.gov (United States)

    Liu, Ya; Zhao, Xin; Hu, Guoqing; Li, Cui; Zhao, Bofeng; Zheng, Zheng

    2016-09-01

    Dual-comb lasers from which asynchronous ultrashort pulses can be simultaneously generated have recently become an interesting research subject. They could be an intriguing alternative to the current dual-laser optical-frequency-comb source with highly sophisticated electronic control systems. If generated through a common light path traveled by all pulses, the common-mode noises between the spectral lines of different pulse trains could be significantly reduced. Therefore, coherent dual-comb generation from a completely common-path, unidirectional lasing cavity would be an interesting territory to explore. In this paper, we demonstrate such a dual-comb lasing scheme based on a nanomaterial saturable absorber with additional pulse narrowing and broadening mechanisms concurrently introduced into a mode-locked fiber laser. The interactions between multiple soliton formation mechanisms result in unusual bifurcation into two-pulse states with quite different characteristics. Simultaneous oscillation of pulses with four-fold difference in pulsewidths and tens of Hz repetition rate difference is observed. The coherence between these spectral-overlapped, picosecond and femtosecond pulses is further verified by the corresponding asynchronous cross-sampling and dual-comb spectroscopy measurements.

  7. Robust equivalent consumption-based controllers for a dual-mode diesel parallel HEV

    International Nuclear Information System (INIS)

    Finesso, Roberto; Spessa, Ezio; Venditti, Mattia

    2016-01-01

    Highlights: • Non-plug-in dual-mode parallel hybrid architecture. • Cross-validation machine-learning for robust equivalent consumption-based controllers. • Optimal control strategy based on fuel consumption, NOx and battery aging. • Impact of different equivalent consumption definitions on HEV performance. • Correlation between vehicle braking energy and SOC variation in the traction stages. - Abstract: New equivalent consumption minimization strategy (ECMS) tools have been developed and applied to identify the optimal control strategy of a dual-mode parallel hybrid electric vehicle equipped with a compression-ignition engine. In this architecture, the electric machine is coupled to the engine through either a single-speed gearbox (torque-coupling) or a planetary gear set (speed-coupling). One of the main novelties of the present study concerns the definition of the instantaneous equivalent consumption (EC) function, which takes into account not only fuel consumption (FC) and the energy flow through the electric components, but also NO_x emissions, battery aging, and the battery SOC. The EC function has been trained using a cross-validation machine-learning technique, based on a genetic algorithm, where the training data set has been selected in order to maximize performances over a testing data set. The adoption of this technique, in conjunction with the new definition of EC, have led to the identification of very robust controllers, which provide an accurate control for different driving scenarios, even when the EC function is not specifically trained on the same missions over which it is tested. To this aim, a data set of fifty driving cycles and six user-defined missions, which cover a total distance of 70–100 km, has been considered as a training driving set. The ECMS controllers can be implemented in a vehicle control unit, and their performance has resulted to be close to that of a dynamic programming tool, which has here been used as benchmark

  8. Formation of multifunctional Fe3O4/Au composite nanoparticles for dual-mode MR/CT imaging applications

    International Nuclear Information System (INIS)

    Hu Yong; Li Jing-Chao; Shen Ming-Wu; Shi Xiang-Yang

    2014-01-01

    Recent advances with iron oxide/gold (Fe 3 O 4 /Au) composite nanoparticles (CNPs) in dual-modality magnetic resonance (MR) and computed tomography (CT) imaging applications are reviewed. The synthesis and assembly of “dumbbelllike” and “core/shell” Fe 3 O 4 /Au CNPs is introduced. Potential applications of some developed Fe 3 O 4 /Au CNPs as contrast agents for dual-mode MR/CT imaging applications are described in detail. (topical review - magnetism, magnetic materials, and interdisciplinary research)

  9. Recent Advances in Cancer Therapy Based on Dual Mode Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Ellas Spyratou

    2017-12-01

    Full Text Available Many tumor-targeted strategies have been used worldwide to limit the side effects and improve the effectiveness of therapies, such as chemotherapy, radiotherapy (RT, etc. Biophotonic therapy modalities comprise very promising alternative techniques for cancer treatment with minimal invasiveness and side-effects. These modalities use light e.g., laser irradiation in an extracorporeal or intravenous mode to activate photosensitizer agents with selectivity in the target tissue. Photothermal therapy (PTT is a minimally invasive technique for cancer treatment which uses laser-activated photoabsorbers to convert photon energy into heat sufficient to induce cells destruction via apoptosis, necroptosis and/or necrosis. During the last decade, PTT has attracted an increased interest since the therapy can be combined with customized functionalized nanoparticles (NPs. Recent advances in nanotechnology have given rise to generation of various types of NPs, like gold NPs (AuNPs, designed to act both as radiosensitizers and photothermal sensitizing agents due to their unique optical and electrical properties i.e., functioning in dual mode. Functionalized AuNPS can be employed in combination with non-ionizing and ionizing radiation to significantly improve the efficacy of cancer treatment while at the same time sparing normal tissues. Here, we first provide an overview of the use of NPs for cancer therapy. Then we review many recent advances on the use of gold NPs in PTT, RT and PTT/RT based on different types of AuNPs, irradiation conditions and protocols. We refer to the interaction mechanisms of AuNPs with cancer cells via the effects of non-ionizing and ionizing radiations and we provide recent existing experimental data as a baseline for the design of optimized protocols in PTT, RT and PTT/RT combined treatment.

  10. Colorimetry and SERS dual-mode detection of telomerase activity: combining rapid screening with high sensitivity.

    Science.gov (United States)

    Zong, Shenfei; Wang, Zhuyuan; Chen, Hui; Hu, Guohua; Liu, Min; Chen, Peng; Cui, Yiping

    2014-01-01

    As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and surface enhanced Raman scattering (SERS) dual-mode telomerase activity detection method, which has several distinctive advantages. First, colorimetric functionality allows rapid preliminary discrimination of telomerase activity by the naked eye. Second, the employment of SERS technique results in greatly improved detection sensitivity. Third, the combination of colorimetry and SERS into one detection system can ensure highly efficacious and sensitive screening of numerous samples. Besides, the avoidance of polymerase chain reaction (PCR) procedures further guarantees fine reliability and simplicity. Generally, the presented method is realized by an "elongate and capture" procedure. To be specific, gold nanoparticles modified with Raman molecules and telomeric repeat complementary oligonucleotide are employed as the colorimetric-SERS bifunctional reporting nanotag, while magnetic nanoparticles functionalized with telomerase substrate oligonucleotide are used as the capturing substrate. Telomerase can synthesize and elongate telomeric repeats onto the capturing substrate. The elongated telomeric repeats subsequently facilitate capturing of the reporting nanotag via hybridization between telomeric repeat and its complementary strand. The captured nanotags can cause a significant difference in the color and SERS intensity of the magnetically separated sediments. Thus both the color and SERS can be used as indicators of the telomerase activity. With fast screening ability and outstanding sensitivity, we anticipate that this method would greatly promote practical application of telomerase-based early-stage cancer diagnosis.

  11. Microscale characterization of the viscoelastic properties of hydrogel biomaterials using dual-mode ultrasound elastography.

    Science.gov (United States)

    Hong, Xiaowei; Stegemann, Jan P; Deng, Cheri X

    2016-05-01

    Characterization of the microscale mechanical properties of biomaterials is a key challenge in the field of mechanobiology. Dual-mode ultrasound elastography (DUE) uses high frequency focused ultrasound to induce compression in a sample, combined with interleaved ultrasound imaging to measure the resulting deformation. This technique can be used to non-invasively perform creep testing on hydrogel biomaterials to characterize their viscoelastic properties. DUE was applied to a range of hydrogel constructs consisting of either hydroxyapatite (HA)-doped agarose, HA-collagen, HA-fibrin, or preosteoblast-seeded collagen constructs. DUE provided spatial and temporal mapping of local and bulk displacements and strains at high resolution. Hydrogel materials exhibited characteristic creep behavior, and the maximum strain and residual strain were both material- and concentration-dependent. Burger's viscoelastic model was used to extract characteristic parameters describing material behavior. Increased protein concentration resulted in greater stiffness and viscosity, but did not affect the viscoelastic time constant of acellular constructs. Collagen constructs exhibited significantly higher modulus and viscosity than fibrin constructs. Cell-seeded collagen constructs became stiffer with altered mechanical behavior as they developed over time. Importantly, DUE also provides insight into the spatial variation of viscoelastic properties at sub-millimeter resolution, allowing interrogation of the interior of constructs. DUE presents a novel technique for non-invasively characterizing hydrogel materials at the microscale, and therefore may have unique utility in the study of mechanobiology and the characterization of hydrogel biomaterials. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. The Development of CyberLearning in Dual-Mode: Higher Education Institutions in Taiwan

    Directory of Open Access Journals (Sweden)

    Yau-Jane Chen

    2002-01-01

    Full Text Available Open and distance education in Taiwan has evolved into the third phase – cyberlearning – conceptualized as teaching and learning interactions mediated entirely through the application of state-of-the-art information and communications technologies (ICT, such as the Internet and World Wide Web. Socio-economic influences, the development of new technologies and a marked shift in learning paradigms have increased the utilization of ICT at all levels of the Taiwanese education system. Since the advent and provision of cyberlearning programs, well over half (56 percent of the conventional universities and colleges have been upgraded to dual-mode higher educational institutions. They offer real-time multicast instructional systems using videoconferencing and cable TV technology, virtual classroom systems via network-based instructional management systems, and curriculum-on-demand systems utilizing video-on-demand technology. Critical success factors in the development of these cyber universities and the opportunities, challenges and implications inherent in these are analyzed. ICT and the provision of cyberlearning have gradually been changing the structure and vision of higher education institutions as well as the entire learning environment and educational systems. Because the Ministry of Education (MOE has initiated a policy on credit-based degrees for cyberlearning courses/ programs, the development of open and distance education is anticipated to hasten the transformation of Taiwan’s education system towards one which will create an ideal learning society in the 21st century.

  13. Micro generation of electricity with gasification gas in a engine generator in dual mode; Microgeracao de eletricidade com gas de gaseificacao num motor gerador dual

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcelo Jose da; Souza, Samuel Nelson Melegari de; Souza, Abel Alves de; Ricieri, Reinaldo P. [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PE (Brazil)], E-mail: marcelo_js07@hotmail.com

    2010-07-01

    Among the alternatives to the increase of world energy demand the use of biomass as energy source is one of the most promising as it contributes to reducing emissions of carbon dioxide in the atmosphere. Gasification is a process technology of biomass energy in a gaseous biofuel. The fuel gas got a low calorific value that can be used in diesel engine in dual mode for power generation in isolated communities. This study aimed to evaluate the reduction in the consumption of oil diesel an engine generator, using gas from gasification of wood. The engine generator brand used, it was a BRANCO, with direct injection power of 10 hp and mated to an electric generator 5,5 kW. The fuel gas was produced in a gasifier type co-current. The engine generator was put on load system from 0.5 kW to 3.5 kW through electric bank of heaters. For the oil diesel savings, the gas was injected mixed with intake air, as the oil diesel was normally injected by the injector of the engine (motor dual). The consumption od diesel was measured diesel by means of a precision scale. It was concluded that the engine converted to dual mode when using the gas for the gasification of wood showed a decrease in diesel consumption by up to 57%. (author)

  14. Pricing Models for Dual-channel Reverse Supply Chain Considering Regional Differences under “Internet Recycling” Mode in China

    Science.gov (United States)

    Wu, Di; Li, Peng; Chen, Juhong

    2018-01-01

    In recent years, the Internet technology has been deeply influencing recycling industry to make it more intelligent and interconnected. However, most existing papers on “Internet Recycling” neglected the problem of pricing strategy under online and offline channels for different levels of recyclers. Moreover, the effect of regional differences has been emphasized a lot in dual-channel forward supply chain, but recycling field has seldom been concerned about it. In this paper, a recycling system consisting of one recycling center and several third-party recyclers (TPR) was investigated based on traditional mode and dual-channel mode. The dual-channel reverse supply chain model is transformed from traditional mode by the introduction of online channel. It involves two recycling modes, as recycling centre for online recovery and “Recycling center+TPR” for offline recovery. By establishing pricing strategies based on Stackelberg game model, the impacts of regional differences were analysed. Finally, numerical analysis was given to illustrate the effectiveness of the pricing mechanisms and strategies.

  15. DUAL MODE OFFERING AS VIABLE APPROACH FOR PROMOTION OF HIGHER EDUCATION IN PAKISTAN

    Directory of Open Access Journals (Sweden)

    Irshad HUSSAIN

    2014-07-01

    Full Text Available Pakistan is a developing with 148 universities and degree awarding institutions including public and private sector. The enrolment as given in the National Educational Policy 2009 was up to 5% only. It reflects greater demands of higher/tertiary education and calls for alternative strategic measures for addressing the issue. An innovative approach was necessary to address the issue of access. Therefore, the Islamia University of Bahawalpur –a formal mode university took an innovative initiative to become a dual mode university by establishing an Institute of Distance Education (IDE in 2011. The institute offered along with others, an M.Phill programme in ten disciplines through distance education mode in semester fall 2011. More than eight hundred applications were received by potential learners against 275 seats. However, after test and interview 189 students were enrolled in M.Phill programme in Applied Psychology, Arabic, Education, English, Media Studies, Islamic Studies, Pakistan Studies, History, Persian, and Urdu. In the beginning, the Institute organized an orientation workshop for learners to guide them studying in distance education system. The programme was offered under semester system and the semester was broke up into two halves –mid-term and final term. The respective departments provided learning materials to students whereas the IDE provided instructional booklet. Submission of two assignments was compulsory for the entire semester; one before mid-term and second before final-term workshop/ examination for each of the courses. Similarly, students’ presence in workshops for 24 hours (12 during mid-term and 12 during final-term workshop for one 3-credit hour course was mandatory. Students’ support services were provided through Skype conference, social media and mobile phones. Students necessarily had to give presentations and submit their assignments after checking their similarity index by using turnitin software. At the

  16. Dual Mode Offering As Viable Approach 
For Promotion Of Higher Education In Pakistan

    Directory of Open Access Journals (Sweden)

    Irshad HUSSAIN

    2014-01-01

    Full Text Available Pakistan is a developing with 148 universities and degree awarding institutions including public and private sector. The enrolment as given in the National Educational Policy 2009 was up to 5% only. It reflects greater demands of higher/tertiary education and calls for alternative strategic measures for addressing the issue. An innovative approach was necessary to address the issue of access. Therefore, the Islamia University of Bahawalpur –a formal mode university took an innovative initiative to become a dual mode university by establishing an Institute of Distance Education (IDE in 2011. The institute offered along with others, an M.Phill programme in ten disciplines through distance education mode in semester fall 2011. More than eight hundred applications were received by potential learners against 275 seats. However, after test and interview 189 students were enrolled in M.Phill programme in Applied Psychology, Arabic, Education, English, Media Studies, Islamic Studies, Pakistan Studies, History, Persian, and Urdu. In the beginning, the Institute organized an orientation workshop for learners to guide them studying in distance education system. The programme was offered under semester system and the semester was broke up into two halves –mid-term and final term. The respective departments provided learning materials to students whereas the IDE provided instructional booklet. Submission of two assignments was compulsory for the entire semester; one before mid-term and second before final-term workshop/ examination for each of the courses. Similarly, students’ presence in workshops for 24 hours (12 during mid-term and 12 during final-term workshop for one 3-credit hour course was mandatory. Students’ support services were provided through Skype conference, social media and mobile phones. Students necessarily had to give presentations and submit their assignments after checking their similarity index by using turnitin software. At the

  17. WE-G-BRA-09: Microsphere Brachytherapy Failure Mode and Effects Analysis in a Dual-Vendor Environment

    International Nuclear Information System (INIS)

    Younge, K C; Lee, C I; Feng, M; Novelli, P; Moran, J M; Prisciandaro, J I

    2015-01-01

    Purpose: To improve the safety and quality of a dual-vendor microsphere brachytherapy program with failure mode and effects analysis (FMEA). Methods: A multidisciplinary team including physicists, dosimetrists, a radiation oncologist, an interventional radiologist, and radiation safety personnel performed an FMEA for our dual-vendor microsphere brachytherapy program employing SIR-Spheres (Sirtex Medical Limited, Australia) and Theraspheres (BTG, England). We developed a program process tree and step-by-step instructions which were used to generate a comprehensive list of failure modes. These modes were then ranked according to severity, occurrence rate, and detectability. Risk priority numbers (RPNs) were calculated by multiplying these three scores together. Three different severity scales were created: one each for harmful effects to the patient, staff, or the institution. Each failure mode was ranked on one or more of these scales. Results: The group identified 164 failure modes for the microsphere program. 113 of these were ranked using the patient severity scale, 52 using the staff severity scale, and 50 using the institution severity scale. The highest ranked items on the patient severity scale were an error in the automated dosimetry worksheet (RPN = 297.5), and the incorrect target specified on the planning study (RPN = 135). Some failure modes ranked differently between vendors, especially those corresponding to dose vial preparation because of the different methods used. Based on our findings, we made several improvements to our QA program, including documentation to easily identify which product is being used, an additional hand calculation during planning, and reorganization of QA steps before treatment delivery. We will continue to periodically review and revise the FMEA. Conclusion: We have applied FMEA to our dual-vendor microsphere brachytherapy program to identify potential key weaknesses in the treatment chain. Our FMEA results were used to

  18. WE-G-BRA-09: Microsphere Brachytherapy Failure Mode and Effects Analysis in a Dual-Vendor Environment

    Energy Technology Data Exchange (ETDEWEB)

    Younge, K C; Lee, C I; Feng, M; Novelli, P; Moran, J M; Prisciandaro, J I [Univ Michigan Medical Center, Ann Arbor, MI (United States)

    2015-06-15

    Purpose: To improve the safety and quality of a dual-vendor microsphere brachytherapy program with failure mode and effects analysis (FMEA). Methods: A multidisciplinary team including physicists, dosimetrists, a radiation oncologist, an interventional radiologist, and radiation safety personnel performed an FMEA for our dual-vendor microsphere brachytherapy program employing SIR-Spheres (Sirtex Medical Limited, Australia) and Theraspheres (BTG, England). We developed a program process tree and step-by-step instructions which were used to generate a comprehensive list of failure modes. These modes were then ranked according to severity, occurrence rate, and detectability. Risk priority numbers (RPNs) were calculated by multiplying these three scores together. Three different severity scales were created: one each for harmful effects to the patient, staff, or the institution. Each failure mode was ranked on one or more of these scales. Results: The group identified 164 failure modes for the microsphere program. 113 of these were ranked using the patient severity scale, 52 using the staff severity scale, and 50 using the institution severity scale. The highest ranked items on the patient severity scale were an error in the automated dosimetry worksheet (RPN = 297.5), and the incorrect target specified on the planning study (RPN = 135). Some failure modes ranked differently between vendors, especially those corresponding to dose vial preparation because of the different methods used. Based on our findings, we made several improvements to our QA program, including documentation to easily identify which product is being used, an additional hand calculation during planning, and reorganization of QA steps before treatment delivery. We will continue to periodically review and revise the FMEA. Conclusion: We have applied FMEA to our dual-vendor microsphere brachytherapy program to identify potential key weaknesses in the treatment chain. Our FMEA results were used to

  19. Optical frequency comb generation based on the dual-mode square microlaser and a nonlinear fiber loop

    Science.gov (United States)

    Weng, Hai-Zhong; Han, Jun-Yuan; Li, Qing; Yang, Yue-De; Xiao, Jin-Long; Qin, Guan-Shi; Huang, Yong-Zhen

    2018-05-01

    A novel approach using a dual-mode square microlaser as the pump source is demonstrated to produce wideband optical frequency comb (OFC). The enhanced nonlinear frequency conversion processes are accomplished in a nonlinear fiber loop, which can reduce the stimulated Brillouin scattering threshold and then generate a dual-mode Brillouin laser with improved optical signal-to-noise ratio. An OFC with 130 nm bandwidth and 76 GHz repetition rate is successfully generated under the four-wave mixing, and the number of the comb lines is enhanced by 26 times compared with the system without fiber loop. In addition, the repetition rate of the comb can be adjusted by changing the injection current of the microlaser. The pulse width of the comb spectrum is also compressed from 3 to 1 ps with an extra amplification-nonlinear process.

  20. Dual-Mode SERS-Fluorescence Immunoassay Using Graphene Quantum Dot Labeling on One-Dimensional Aligned Magnetoplasmonic Nanoparticles.

    Science.gov (United States)

    Zou, Fengming; Zhou, Hongjian; Tan, Tran Van; Kim, Jeonghyo; Koh, Kwangnak; Lee, Jaebeom

    2015-06-10

    A novel dual-mode immunoassay based on surface-enhanced Raman scattering (SERS) and fluorescence was designed using graphene quantum dot (GQD) labels to detect a tuberculosis (TB) antigen, CFP-10, via a newly developed sensing platform of linearly aligned magnetoplasmonic (MagPlas) nanoparticles (NPs). The GQDs were excellent bilabeling materials for simultaneous Raman scattering and photoluminescence (PL). The one-dimensional (1D) alignment of MagPlas NPs simplified the immunoassay process and enabled fast, enhanced signal transduction. With a sandwich-type immunoassay using dual-mode nanoprobes, both SERS signals and fluorescence images were recognized in a highly sensitive and selective manner with a detection limit of 0.0511 pg mL(-1).

  1. A Comparative Study of Voltage, Peak Current and Dual Current Mode Control Methods for Noninverting Buck-Boost Converter

    Directory of Open Access Journals (Sweden)

    M. Č. Bošković

    2016-06-01

    Full Text Available This paper presents a comparison of voltage mode control (VMC and two current mode control (CMC methods of noninverting buck-boost converter. The converter control-to-output transfer function, line-to-output transfer function and the output impedance are obtained for all methods by averaging converter equations over one switching period and applying small-signal linearization. The obtained results are required for the design procedure of feedback compensator to keep a system stable and robust. A comparative study of VMC, peak current mode control (PCMC and dual-current mode control (DCMC is performed. Performance evaluation of the closed-loop system with obtained compensator between these methods is performed via numerical simulations.

  2. Structural Design of Dual-Mode Ramjets and Associated System Issues (Conception structurale des statoreacteurs mixtes et defis systeme associes)

    Science.gov (United States)

    2010-09-01

    Institute PAO Protection Against Oxidation RBCC Rocket Based Combined Cycle RSL Reusable Space Launchers SSTO Single Stage to Orbit TOW Take-Off Weight...Orbit) or Single Stage To Orbit ( SSTO ) vehicles, or other kind of hypersonic vehicles. For example, in the scope of the French PREPHA program, the...study of a generic SSTO vehicle led to conclusion that the best type of airbreathing engine could be the dual-mode ramjet (subsonic then supersonic

  3. High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

    OpenAIRE

    Kang, Bong Jin; Park, Jinhyoung; Kim, Jieun; Kim, Hyung Ham; Lee, Changyang; Hwang, Jae Youn; Lien, Ching-Ling; Shung, K. Kirk

    2015-01-01

    Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 ...

  4. Simulation de Ia propagation de fissures dans les solides elastiques en modes mixtes par Ia methode des equations integrales duales

    OpenAIRE

    Kebir , Hocine; Roelandt , Jean Marc; Gaudin , Jocelyn

    2000-01-01

    International audience; The present paper is concerned with the effective numerical implementation of the two dimensional Dual Boundary element method to analyse the mixed-mode crack growth All the boundaries are discretized with discontinuous quadratic boundary elements and the crack-tip is modeled by singular elements that exactly represent the strain field singularity $1/\\sqrt{r}$. The Stress lntensity Factors can be computed very accurately from the crack opening dis placement at collocat...

  5. Detecting and mitigating inverter aging

    International Nuclear Information System (INIS)

    Gunther, W.E.; Taylor, J.H.; Aggarwal, S.K.

    1988-01-01

    Nuclear power plants use inverters to supply power to safety-related equipment, instrumentation, and controls. They convert direct current (dc) to alternating current (ac) power, thereby making low voltage ac power available even under a station blackout condition. As part of the U.S. NRC's nuclear plant aging research (NPAR) program, the operating experience of this equipment has been analyzed to determine the dominant failure modes and causes. This paper summarizes that data, and then describes methods which can be employed to detect inverter degradation prior to failure, as well as methods to minimize the failure effects. In both cases, the mitigation of inverter aging is emphasized

  6. Highly Luminescent Dual Mode Polymeric Nanofiber-Based Flexible Mat for White Security Paper and Encrypted Nanotaggant Applications.

    Science.gov (United States)

    Gangwar, Amit Kumar; Gupta, Ashish; Kedawat, Garima; Kumar, Pawan; Singh, Bhanu Pratap; Singh, Nidhi; Srivastava, Avanish K; Dhakate, Sanjay R; Gupta, Bipin Kumar

    2018-05-23

    Increasing counterfeiting of important data, currency, stamp papers, branded products etc., has become a major security threat which could lead to serious damage to the global economy. Consequences of such damage are compelling for researchers to develop new high-end security features to address full-proof solutions. Herein, we report a dual mode flexible highly luminescent white security paper and nanotaggants composed of nanophosphors incorporated in polymer matrix to form a nanofiber-based mat for anti-counterfeiting applications. The dual mode nanofibers are fabricated by electrospinning technique by admixing the composite of NaYF 4 :Eu 3+ @NaYF 4 :Yb 3+ , Er 3+ nanophosphors in the polyvinyl alcohol solution. This flexible polymer mat derived from nanofibers appears white in daylight, while emitting strong red (NaYF 4 :Eu 3+ ) and green (NaYF 4 :Yb 3+ , Er 3+ ) colors at excitation wavelengths of 254 nm and 980 nm, respectively. These luminescent nanofibers can also be encrypted as a new class of nanotaggants to protect confidential documents. These obtained results suggest that highly luminescent dual mode polymeric nanofiber-based flexible white security paper and nanotaggants could offer next-generation high-end unique security features against counterfeiting. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Colorimetric and Fluorescent Dual Mode Sensing of Alcoholic Strength in Spirit Samples with Stimuli-Responsive Infinite Coordination Polymers.

    Science.gov (United States)

    Deng, Jingjing; Ma, Wenjie; Yu, Ping; Mao, Lanqun

    2015-07-07

    This study demonstrates a new strategy for colorimetric and fluorescent dual mode sensing of alcoholic strength (AS) in spirit samples based on stimuli-responsive infinite coordination polymers (ICPs). The ICP supramolecular network is prepared with 1,4-bis(imidazol-1-ylmethyl)benzene (bix) as the ligand and Zn(2+) as the central metal ion in ethanol, in which rhodamine B (RhB) is encapsulated through self-adaptive chemistry. In pure ethanol solvent, the as-formed RhB/Zn(bix) is well dispersed and quite stable. However, the addition of water into the ethanol dispersion of RhB/Zn(bix) destroys Zn(bix) network structure, resulting in the release of RhB from ICP into the solvent. As a consequence, the solvent displays the color of released RhB and, at the meantime, turns on the fluorescence of RhB, which constitutes a new mechanism for colorimetric and fluorescent dual mode sensing of AS in commercial spirit samples. With the method developed here, we could distinguish the AS of different commercial spirit samples by the naked eye within a wide linear range from 20 to 100% vol and by monitoring the increase of fluorescent intensity of the released RhB. This study not only offers a new method for on-spot visible detection of AS in commercial spirit samples, but also provides a strategy for designing dual mode sensing mechanisms for different analytical purposes based on novel stimuli-responsive materials.

  8. Melanin-originated carbonaceous dots for triple negative breast cancer diagnosis by fluorescence and photoacoustic dual-mode imaging.

    Science.gov (United States)

    Xiao, Wei; Li, Yuan; Hu, Chuan; Huang, Yuan; He, Qin; Gao, Huile

    2017-07-01

    Carbonaceous dots exhibit increasing applications in diagnosis and drug delivery due to excellent photostability and biocompatibility properties. However, relative short excitation and emission of melanin carbonaceous dots (MCDs) limit the applicability in fluorescence bioimaging. Furthermore, the generally poor spatial resolution of fluorescence imaging limits potential in vivo applications. Due to a variety of beneficial properties, in this study, MCDs were prepared exhibiting great potential in fluorescence and photoacoustic dual-mode bioimaging. The MCDs exhibited a long excitation peak at 615nm and emission peak at 650nm, further highlighting the applicability in fluorescence imaging, while the absorbance peak at 633nm renders MCDs suitable for photoacoustic imaging. In vivo, the photoacoustic signal of MCDs was linearly correlated with the concentration of MCDs. Moreover, the MCDs were shown to be taken up into triple negative breast cancer cell line 4T1 in both a time- and concentration-dependent manner. In vivo fluorescence and photoacoustic imaging of subcutaneous 4T1 tumor demonstrated that MCDs could passively target triple negative breast cancer tissue by enhanced permeability and retention effects and may therefore be used for tumor dual-mode imaging. Furthermore, fluorescence distribution in tissue slices suggested that MCDs may distribute in 4T1 tumor with high efficacy. In conclusion, the MCDs studied offer potential application in fluorescence and photoacoustic dual-mode imaging. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Multiple dual mode counter-current chromatography with variable duration of alternating phase elution steps.

    Science.gov (United States)

    Kostanyan, Artak E; Erastov, Andrey A; Shishilov, Oleg N

    2014-06-20

    The multiple dual mode (MDM) counter-current chromatography separation processes consist of a succession of two isocratic counter-current steps and are characterized by the shuttle (forward and back) transport of the sample in chromatographic columns. In this paper, the improved MDM method based on variable duration of alternating phase elution steps has been developed and validated. The MDM separation processes with variable duration of phase elution steps are analyzed. Basing on the cell model, analytical solutions are developed for impulse and non-impulse sample loading at the beginning of the column. Using the analytical solutions, a calculation program is presented to facilitate the simulation of MDM with variable duration of phase elution steps, which can be used to select optimal process conditions for the separation of a given feed mixture. Two options of the MDM separation are analyzed: 1 - with one-step solute elution: the separation is conducted so, that the sample is transferred forward and back with upper and lower phases inside the column until the desired separation of the components is reached, and then each individual component elutes entirely within one step; 2 - with multi-step solute elution, when the fractions of individual components are collected in over several steps. It is demonstrated that proper selection of the duration of individual cycles (phase flow times) can greatly increase the separation efficiency of CCC columns. Experiments were carried out using model mixtures of compounds from the GUESSmix with solvent systems hexane/ethyl acetate/methanol/water. The experimental results are compared to the predictions of the theory. A good agreement between theory and experiment has been demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Dual mode antimony electrode for simultaneous measurements of PO2 and pH.

    Science.gov (United States)

    Sjöberg, F; Nilsson, G

    2000-01-01

    In biomedical research and clinical medicine there is a demand for potent sensors to measure the components that make up blood gas analyses. Today, as when the electrochemical PO2, PCO2 and pH electrodes were first introduced, these measurements are usually made with the same type of sensor technology. The aims of the present study were, firstly, to find out whether the platinum cathode in the Clark electrode can be replaced by antimony for oxygen measurements (amperometry (A)); secondly, whether, during oxygen measurements, the inherent corrosion potential of the antimony metal can be used for measurement of pH in the same measurement area (potentiometry (P)). An electrode of purified, crystallographically orientated monocrystalline antimony (COMA) connected to a reference electrode (silver-silver chloride) was used for the P measurements. Measurements of A (at -900 mV) and P were made in an aqueous environment regulated for oxygen, pH, and temperature. Reproducible oxygen sensitivities of 0.925 nA/% oxygen (2% CV (coefficient of variation)) (A), 10.7 mV/% (P), and 0.7 mV/% (P) were found in the oxygen range: 0-21%, <5%, and above 5%, respectively. The pH sensitivity was 57 mV/pH unit (P). Oxygen and pH measurements were less accurate at oxygen concentrations close to 0%. Both the oxygen and pH part of the composite electrode signal can be identified by this dual mode technique (A and P). The sensor seems to be promising as it provides measurements of two separate variables (oxygen and pH) and also has the desirable characteristics of a solid state sensor.

  11. Saline-enhanced hepatic radiofrequency ablation using a perfused-cooled electrode: comparison of dual probe bipolar mode with monopolar and single probe bipolar modes

    International Nuclear Information System (INIS)

    Lee, Jeong Min; Han, Joon Koo; Kim, Se Hyung; Lee, Jae Young; Kim, Dae Jin; Lee, Min Woo; Cho, Gyung Goo; Han, Chang Jin; Choi, Byung Ihn

    2004-01-01

    To determine whether saline-enhanced dual probe bipolar radiofrequency ablation (RFA) using perfused-cooled electrodes shows better in-vitro efficiency than monopolar or single probe bipolar RFA in creating larger coagulation necrosis. RF was applied to excised bovine livers in both bipolar and monopolar modes using a 200W generator (CC-3; Radionics) and the perfused-cooled electrodes for 10 mins. After placing single or double perfused-cooled electrodes in the explanted liver, 30 ablation zones were created at three different regimens: group A; saline-enhanced monopolar RFA, group B; saline-enhanced single probe bipolar RFA, and group C; saline-enhanced dual probe bipolar RFA. During RFA, we measured the tissue temperature at 15mm from the electrode. The dimensions of the ablation zones and changes in the impedance currents and liver temperature during RFA were then compared between the groups. The mean current values were higher for monopolar mode (group A) than for the bipolar modes (group B and C): 1550 ± 25 mA in group A, 764 ±189 mA in group B and 819 ± 98 mA in group C(ρ 3 in group A, 23.7 ±3.8 cm 3 in group B, and 34.2 ± 5.1 cm 3 in group C(ρ 0.05). The temperature at 15 mm from the electrode was higher in group C than in the other groups: 70 ± 18 .deg. C in group A, 59 ± 23 .deg. C in group B and 96 ± 16 .deg. C in group C (ρ < 0.05). Saline-enhanced bipolar RFA using dual perfused-cooled electrodes increases the dimension of the ablation zone more efficiently than monopolar RFA or single probe bipolar RFA

  12. Dual-mode optical fiber-based tweezers for robust trapping and manipulation of absorbing particles in air

    Science.gov (United States)

    Sil, Souvik; Kanti Saha, Tushar; Kumar, Avinash; Bera, Sudipta K.; Banerjee, Ayan

    2017-12-01

    We develop an optical tweezers system using a single dual-mode optical fiber where mesoscopic absorbing particles can be trapped in three dimensions and manipulated employing photophoretic forces. We generate a superposition of fundamental and first order Hermite-Gaussian beam modes by the simple innovation of coupling a laser into a commercial optical fiber designed to be single mode for a wavelength higher than that of the laser. We achieve robust trapping of the absorbing particles for hours using both the pure fundamental and superposition mode beams and attain large manipulation velocities of ˜5 mm s-1 in the axial direction and ˜0.75 mm s-1 in the radial direction. We then demonstrate that the superposition mode is more effective in trapping and manipulation compared to the fundamental mode by around 80%, which may be increased several times by the use of a pure first order Hermite-Gaussian mode. The work has promising implications for trapping and spectroscopy of aerosols in air using simple optical fiber-based traps.

  13. Asymmetric dual-loop feedback to suppress spurious tones and reduce timing jitter in self-mode-locked quantum-dash lasers emitting at 155 μm

    Science.gov (United States)

    Asghar, Haroon; McInerney, John G.

    2017-09-01

    We demonstrate an asymmetric dual-loop feedback scheme to suppress external cavity side-modes induced in self-mode-locked quantum-dash lasers with conventional single and dual-loop feedback. In this letter, we achieved optimal suppression of spurious tones by optimizing the length of second delay time. We observed that asymmetric dual-loop feedback, with large (~8x) disparity in cavity lengths, eliminates all external-cavity side-modes and produces flat RF spectra close to the main peak with low timing jitter compared to single-loop feedback. Significant reduction in RF linewidth and reduced timing jitter was also observed as a function of increased second feedback delay time. The experimental results based on this feedback configuration validate predictions of recently published numerical simulations. This interesting asymmetric dual-loop feedback scheme provides simplest, efficient and cost effective stabilization of side-band free optoelectronic oscillators based on mode-locked lasers.

  14. Single DV-DXCCII Based Voltage Controlled First Order All-pass Filter with Inverting and Non-inverting responses

    Directory of Open Access Journals (Sweden)

    B Chaturvedi

    2015-12-01

    Full Text Available In this paper, a new voltage controlled first order all-pass filter is presented. The proposed circuit employs a single differential voltage dual-X second generation current conveyor (DV-DXCCII and a grounded capacitor only. The proposed all-pass filter provides both inverting and non inverting voltage-mode outputs from the same configuration simultaneously without any matching condition. Non-ideal analysis along with sensitivity analysis is also investigated. The proposed circuit has low active and passive sensitivities. As an application the proposed all-pass filter is connected in cascade to get higher order filter. The theoretical results are validated thorough PSPICE simulations using TSMC 0.18µm CMOS process parameters.

  15. Realization of Current Mode Universal Filter and a Dual-Mode Single Resistance Controlled Quadrature Oscillator Employing VDCC and Only Grounded Passive Elements

    Directory of Open Access Journals (Sweden)

    Manish Gupta

    2017-01-01

    Full Text Available The manuscript presents a circuit that can act as a universal filter as well as a single resistence controlled oscillator by unpretentiously changing the switch positions. The circuit employs only two active devices and all grounded passive elements. The utilization of only grounded passive components makes this circuit a better choice for integrated circuit implementation. The current mode biquadratic filter offers all the five basic responses along with independent tunability of its quality factor. The dual-mode quadrature sinusoidal oscillator offers explicit current outputs along with voltage outputs. The circuit also offers a simple and uncoupled condition of oscillation and frequency of oscillation. The typical analysis such as non-ideal, sensitivity and parasitic analysis along with the regular simulation results as well as experimental results are exposed here, to strengthen the design idea.

  16. High-power terahertz optical pulse generation with a dual-wavelength harmonically mode-locked Yb:YAG laser

    International Nuclear Information System (INIS)

    Zhuang, W Z; Chang, M T; Su, K W; Huang, K F; Chen, Y F

    2013-01-01

    We report on high-power terahertz optical pulse generation with a dual-wavelength harmonically mode-locked Yb:YAG laser. A semiconductor saturable absorber mirror is developed to achieve synchronously mode-locked operation at two spectral bands centered at 1031.67 and 1049.42 nm with a pulse duration of 1.54 ps and a pulse repetition rate of 80.3 GHz. With a diamond heat spreader to improve the heat removal efficiency, the average output power can be up to 1.1 W at an absorbed pump power of 5.18 W. The autocorrelation traces reveal that the mode-locked pulse is modulated with a beat frequency of 4.92 THz and displays a modulation depth to be greater than 80%. (paper)

  17. Compact 84 GHz passive mode-locked fiber laser using dual-fiber coupled fused-quartz microresonator

    Science.gov (United States)

    Liu, Tze-An; Hsu, Yung; Chow, Chi-Wai; Chuang, Yi-Chen; Ting, Wei-Jo; Wang, Bo-Chun; Peng, Jin-Long; Chen, Guan-Hong; Chang, Yuan-Chia

    2017-10-01

    We propose and demonstrate a compact and portable-size 84-GHz passive mode-locked fiber laser, in which a dual-fiber coupled fused-quartz microresonator is employed as the intracavity optical comb filter as well as the optical nonlinear material for optical frequency comb generation. About eight coherent optical tones can be generated in the proposed fiber laser. The 20-dB bandwidth is larger than 588 GHz. The full-width half-maximum pulse-width of the proposed laser is 2.5 ps. We also demonstrate the feasibility of using the proposed passive mode-locked fiber laser to carry a 5-Gbit/s on-off-keying signal and transmit over 20-km standard single mode fiber. A 7% forward error correction requirement can be achieved, showing the proposed fiber laser can be a potential candidate for fiber-wireless applications.

  18. PERFORMANCE, EMISSION, AND COMBUSTION CHARACTERISTICS OF A CI ENGINE USING LIQUID PETROLEUM GAS AND NEEM OIL IN DUAL FUEL MODE

    Directory of Open Access Journals (Sweden)

    Palanimuthu Vijayabalan

    2010-01-01

    Full Text Available Increased environmental awareness and depletion of resources are driving the industries to develop viable alternative fuels like vegetable oils, compresed natural gas, liquid petroleum gas, producer gas, and biogas in order to provide suitable substitute to diesel for compression ignition engine. In this investigation, a single cylinder, vertical, air-cooled diesel engine was modified to use liquid petroleum gas in dual fuel mode. The liquefied petroleum gas, was mixed with air and supplied through intake manifold. The liquid fuel neem oil or diesel was injected into the combustion chamber. The performance, emission, and combustion characteristics were studied and compared for neat fuel and dual fuel mode. The experimental results on dual fuel engine show a reduction in oxides of nitrogen up to 70% of the rated power and smoke in the entire power range. However the brake thermal efficiency was found decreased in low power range due to lower calorific value of liquid petroleum gas, and increase in higher power range due to the complete burning of liquid petroleum gas. Hydrocarbon and carbon monoxide emissions were increased significantly at lower power range and marginal variation in higher power range.

  19. Single Stator Dual PM Rotor Synchronous Machine with two-frequency single-inverter control, for the propulsion of hybrid electric vehicles

    Directory of Open Access Journals (Sweden)

    Topor Marcel

    2017-01-01

    Full Text Available This paper introduces a novel brushless, single winding and single stator, dual PM rotor axial-air-gap machine capable to deliver independently torque at the two rotors by adequate dual vector control. The proposed topologies, the circuit model, controlled dynamics simulation and preliminary 3D FEM torque production on a case study constitute the core of the paper. The proposed dual mechanical port system should be instrumental in parallel (with planetary gears or series hybrid electric vehicles (HEV aiming at a more compact and efficient electric propulsion system solution.

  20. Decentralized Sliding Mode Observer Based Dual Closed-Loop Fault Tolerant Control for Reconfigurable Manipulator against Actuator Failure.

    Directory of Open Access Journals (Sweden)

    Bo Zhao

    Full Text Available This paper considers a decentralized fault tolerant control (DFTC scheme for reconfigurable manipulators. With the appearance of norm-bounded failure, a dual closed-loop trajectory tracking control algorithm is proposed on the basis of the Lyapunov stability theory. Characterized by the modularization property, the actuator failure is estimated by the proposed decentralized sliding mode observer (DSMO. Moreover, the actuator failure can be treated in view of the local joint information, so its control performance degradation is independent of other normal joints. In addition, the presented DFTC scheme is significantly simplified in terms of the structure of the controller due to its dual closed-loop architecture, and its feasibility is highly reflected in the control of reconfigurable manipulators. Finally, the effectiveness of the proposed DFTC scheme is demonstrated using simulations.

  1. Decentralized Sliding Mode Observer Based Dual Closed-Loop Fault Tolerant Control for Reconfigurable Manipulator against Actuator Failure

    Science.gov (United States)

    Zhao, Bo; Li, Yuanchun

    2015-01-01

    This paper considers a decentralized fault tolerant control (DFTC) scheme for reconfigurable manipulators. With the appearance of norm-bounded failure, a dual closed-loop trajectory tracking control algorithm is proposed on the basis of the Lyapunov stability theory. Characterized by the modularization property, the actuator failure is estimated by the proposed decentralized sliding mode observer (DSMO). Moreover, the actuator failure can be treated in view of the local joint information, so its control performance degradation is independent of other normal joints. In addition, the presented DFTC scheme is significantly simplified in terms of the structure of the controller due to its dual closed-loop architecture, and its feasibility is highly reflected in the control of reconfigurable manipulators. Finally, the effectiveness of the proposed DFTC scheme is demonstrated using simulations. PMID:26181826

  2. Vibrational correlation between conjugated carbonyl and diazo modes studied by single- and dual-frequency two-dimensional infrared spectroscopy

    Science.gov (United States)

    Maekawa, Hiroaki; Sul, Soohwan; Ge, Nien-Hui

    2013-08-01

    We have applied infrared three-pulse photon echo and single- and dual-frequency 2D IR spectroscopy to the ester Cdbnd O and diazo Ndbnd N stretching modes in ethyl diazoacetate (EDA), and investigated their vibrational frequency fluctuations and correlation. The two modes exhibit different vibrational dynamics and 2D lineshape, which are well simulated by frequency-frequency correlation functions (FFCFs) with two decaying components. Although the FT IR spectrum shows a single Cdbnd O band, absolute magnitude 2D IR nonrephasing spectrum displays spectral signatures supporting the presence of cis and trans conformations. The cross-peak inclined toward the anti-diagonal in the dual-frequency 2D IR spectrum, indicating that the frequency fluctuations of the two modes are anticorrelated. This behavior is attributed to anticorrelated change in the bond orders when solvent and structural fluctuations causes EDA to adopt a different mixture of the two dominant resonance structures. The effects of cross FFCF on the cross-peak line shape are discussed.

  3. High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

    Science.gov (United States)

    Kang, Bong Jin; Park, Jinhyoung; Kim, Jieun; Kim, Hyung Ham; Lee, Changyang; Hwang, Jae Youn; Lien, Ching-Ling; Shung, K. Kirk

    2015-01-01

    Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 MHz high-frequency array ultrasound imaging system. Phantom studies show that the Doppler flow mode of the dual mode is capable of measuring the flow velocity from 0.1 to 15 cm s−1 with high accuracy (p-value = 0.974 > 0.05). In the in vivo study of zebrafish, both TD and Doppler flow signals were simultaneously obtained from the zebrafish heart for the first time, and the synchronized valve motions with the blood flow signals were identified. In the longitudinal study on the zebrafish heart regeneration, the parameters for diagnosing the diastolic dysfunction, for example, E/Em < 10, E/A < 0.14 for wild-type zebrafish, were measured, and the type of diastolic dysfunction caused by the amputation was found to be similar to the restrictive filling. The diastolic function was fully recovered within four weeks post-amputation. PMID:25505135

  4. Thermal management and performance evaluation of a dual bi-directional, soft-switched IGBT-based inverter for the 1st autonomous microgrid power system in Taiwan under various operating conditions

    Science.gov (United States)

    Chang, Tien-Chan; Fuh, Yiin-Kuen; Lu, Hong-Yi; Tu, Sheng-Xun

    2016-06-01

    The thermal management of the inverter system is of great importance since very high voltage/current will be switched intermittently and/or continuously and high temperature is excruciably detrimental to the service life of electronics, especially for the switching devices such as insulated gate bipolar transistor (IGBT). In this study, a newly developed dual bi-directional IGBT-based inverter in conjunction with autonomous microgrid system is investigated with particular focus on the thermal management and performance evaluation under various operation conditions. Locally enhanced heat transfer approach such as oblique orientation and heat dissipating materials are experimentally investigated. The studied inverter system is initially packaged by a galvanized steel plate (size 62 × 48 × 18 cm) and the switching power is set in the range of 0.5-3 kW. The module is operated at the switching and pulse frequencies of 60 Hz and 20 kHz, respectively. The adoption of heat dissipating material in either paste or film form had experimentally shown to possess the flexibility tailoring heat transfer performance locally. Experimental studies of heat dissipating film with various hotspot scenarios showed that the temperature difference can be appreciably reduced as much as 13.1 and 15.4 °C, respectively with facilitation of one- and two-layers of heat dissipating film. From the measurement results, the measured peak temperature is highly dominated by the thickness of heat dissipating film, showing the dominance of thickness-dependent thermal resistance and resultant heat accumulation phenomena.

  5. Electron heating mode transition induced by mixing radio frequency and ultrahigh frequency dual frequency powers in capacitive discharges

    International Nuclear Information System (INIS)

    Sahu, B. B.; Han, Jeon G.

    2016-01-01

    Electron heating mode transitions induced by mixing the low- and high-frequency power in dual-frequency nitrogen discharges at 400 mTorr pressure are presented. As the low-frequency (13.56 MHz) power decreases and high-frequency (320 MHz) power increases for the fixed power of 200 W, there is a transition of electron energy distribution function (EEDF) from Druyvesteyn to bi-Maxwellian type characterized by a distinguished warm electron population. It is shown that this EEDF evolution is attributed to the transition from collisional to collisionless stochastic heating of the low-energy electrons.

  6. Optimal control of mode transition for four-wheel-drive hybrid electric vehicle with dry dual-clutch transmission

    Science.gov (United States)

    Zhao, Zhiguo; Lei, Dan; Chen, Jiayi; Li, Hangyu

    2018-05-01

    When the four-wheel-drive hybrid electric vehicle (HEV) equipped with a dry dual clutch transmission (DCT) is in the mode transition process from pure electrical rear wheel drive to front wheel drive with engine or hybrid drive, the problem of vehicle longitudinal jerk is prominent. A mode transition robust control algorithm which resists external disturbance and model parameter fluctuation has been developed, by taking full advantage of fast and accurate torque (or speed) response of three electrical power sources and getting the clutch of DCT fully involved in the mode transition process. Firstly, models of key components of driveline system have been established, and the model of five-degrees-of-freedom vehicle longitudinal dynamics has been built by using a Uni-Tire model. Next, a multistage optimal control method has been produced to realize the decision of engine torque and clutch-transmitted torque. The sliding-mode control strategy for measurable disturbance has been proposed at the stage of engine speed dragged up. Meanwhile, the double tracking control architecture that integrates the model calculating feedforward control with H∞ robust feedback control has been presented at the stage of speed synchronization. Finally, the results from Matlab/Simulink software and hardware-in-the-loop test both demonstrate that the proposed control strategy for mode transition can not only coordinate the torque among different power sources and clutch while minimizing vehicle longitudinal jerk, but also provide strong robustness to model uncertainties and external disturbance.

  7. Dual-wavelength passive and hybrid mode-locking of 3, 4.5 and 10 GHz InAs/InP(100) quantum dot lasers

    NARCIS (Netherlands)

    Tahvili, M.S.; Du, L.; Heck, M.J.R.; Nötzel, R.; Smit, M.K.; Bente, E.A.J.M.

    2012-01-01

    We present an investigation of passive and hybrid mode-locking in Fabry-Pérot type two-section InAs/InP(100) quantum dot lasers that show dual wavelength operation. Over the whole current and voltage range for mode-locking of these lasers, the optical output spectra show two distinct lobes. The two

  8. Covalent Organic Framework Functionalized with 8-Hydroxyquinoline as a Dual-Mode Fluorescent and Colorimetric pH Sensor.

    Science.gov (United States)

    Chen, Long; He, Linwei; Ma, Fuyin; Liu, Wei; Wang, Yaxing; Silver, Mark A; Chen, Lanhua; Zhu, Lin; Gui, Daxiang; Diwu, Juan; Chai, Zhifang; Wang, Shuao

    2018-05-09

    Real-time and accurate detection of pH in aqueous solution is of great significance in chemical, environmental, and engineering-related fields. We report here the use of 8-hydroxyquinoline-functionalized covalent organic framework (COF-HQ) for dual-mode pH sensing. In the fluorescent mode, the emission intensity of COF-HQ weakened as the pH decreased, and also displayed a good linear relationship against pH in the range from 1 to 5. In addition, COF-HQ showed discernible color changes from yellow to black as the acidity increased and can be therefore used as a colorimetric pH sensor. All these changes are reversible and COF-HQ can be recycled for multiple detection runs owing to its high hydrolytical stability. It can be further assembled into a mixed matrix membrane for practical applications.

  9. Reproducibility of trabecular bone score with different scan modes using dual-energy X-ray absorptiometry: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Bandirali, Michele; Messina, Carmelo [Universita degli Studi di Milano, Scuola di Specializzazione in Radiodiagnostica, Milano (Italy); Di Leo, Giovanni [Unita di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese (Italy); Pastor Lopez, Maria Juana; Ulivieri, Fabio M. [Servizio di Medicina Nucleare, Ospedale Maggiore, Mineralometria Ossea Computerizzata e Ambulatorio Malattie Metabolismo Minerale e Osseo, Milano (Italy); Mai, Alessandro [Universita degli Studi di Milano, Tecniche di Radiologia Medica, per Immagini e Radioterapia, Milano (Italy); Sardanelli, Francesco [Unita di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese (Italy); Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, San Donato Milanese (Italy)

    2014-08-12

    The trabecular bone score (TBS) accounts for the bone microarchitecture and is calculated on dual-energy X-ray absorptiometry (DXA). We estimated the reproducibility of the TBS using different scan modes compared to the reproducibility bone mineral density (BMD). A spine phantom was used with a Hologic QDR-Discovery A densitometer. For each scan mode [fast array, array, high definition (HD)], 25 scans were automatically performed without phantom repositioning; a further 25 scans were performed with phantom repositioning. For each scan, the TBS was obtained. The coefficient of variation (CoV) was calculated as the ratio between standard deviation and mean; percent least significant change (LSC%) as 2.8 x CoV; reproducibility as the complement to 100 % of LSC%. Differences among scan modes were assessed using ANOVA. Without phantom repositioning, the mean TBS (mm{sup -1}) was: 1.352 (fast array), 1.321 (array), and 1.360 (HD); with phantom repositioning, it was 1.345, 1.332, and 1.362, respectively. Reproducibility of the TBS without phantom repositioning was 97.7 % (fast array), 98.3 % (array), and 98.2 % (HD); with phantom repositioning, it was 97.9 %, 98.7 %, and 98.4 %, respectively. LSC% was ≤2.26 %. Differences among scan modes were all statistically significant (p ≤ 0.019). Reproducibility of BMD was 99.1 % with all scan modes, while LSC% was from 0.86 % to 0.91 %. Reproducibility error of the TBS was 2-3-fold higher than that of BMD. Although statistically significant, differences in TBS among scan modes were within the highest LSC%. Thus, the three scan modes can be considered interchangeable. (orig.)

  10. Multiple low frequency dual reference PWM control of a grid connected photovoltaic three phase NPC inverter with DC/DC boost converter

    Directory of Open Access Journals (Sweden)

    Mechouma Rabiaa

    2014-01-01

    Full Text Available In recent years, power demand of industrial applications has increased significantly reaching some megawatts. The use of multilevel converters for applications of medium and high powers is proposed as a solution to drawback semiconductor technology. A multilevel converter not only achieves high power ratings, but also enables the use of renewable energy sources. Renewable energy sources such as photovoltaic can be easily interfaced to a multilevel converter system for a high power application. This paper presents the simulation study in Matlab/Simulink of a grid connected photovoltaic three phase Neutral Point Clamped (NPC inverter with DC/DC boost converter for constant and variable solar radiation.

  11. 2-D modeling of dual-mode acoustic phonon excitation of a triangular nanoplate

    Science.gov (United States)

    Tai, Po-Tse; Yu, Pyng; Tang, Jau

    2010-08-01

    In this theoretical work, we investigated coherent phonon excitation of a triangular nanoplate based on 2-D Fermi-Pasta-Ulam lattice model. Based on the two-temperature model commonly used in description of laser heating of metals, we considered two kinds of forces related to electronic and lattice stresses. Based on extensive simulation and analysis, we identified two major planar phonon modes, namely, a standing wave mode related to the triangle bisector and another mode corresponding to half of the side length. This work elucidates the roles of laser-induced electronic stress and lattice stress in controlling the initial phase and the amplitude ratio between these two phonon modes.

  12. A Dual-Mode Large-Arrayed CMOS ISFET Sensor for Accurate and High-Throughput pH Sensing in Biomedical Diagnosis.

    Science.gov (United States)

    Huang, Xiwei; Yu, Hao; Liu, Xu; Jiang, Yu; Yan, Mei; Wu, Dongping

    2015-09-01

    The existing ISFET-based DNA sequencing detects hydrogen ions released during the polymerization of DNA strands on microbeads, which are scattered into microwell array above the ISFET sensor with unknown distribution. However, false pH detection happens at empty microwells due to crosstalk from neighboring microbeads. In this paper, a dual-mode CMOS ISFET sensor is proposed to have accurate pH detection toward DNA sequencing. Dual-mode sensing, optical and chemical modes, is realized by integrating a CMOS image sensor (CIS) with ISFET pH sensor, and is fabricated in a standard 0.18-μm CIS process. With accurate determination of microbead physical locations with CIS pixel by contact imaging, the dual-mode sensor can correlate local pH for one DNA slice at one location-determined microbead, which can result in improved pH detection accuracy. Moreover, toward a high-throughput DNA sequencing, a correlated-double-sampling readout that supports large array for both modes is deployed to reduce pixel-to-pixel nonuniformity such as threshold voltage mismatch. The proposed CMOS dual-mode sensor is experimentally examined to show a well correlated pH map and optical image for microbeads with a pH sensitivity of 26.2 mV/pH, a fixed pattern noise (FPN) reduction from 4% to 0.3%, and a readout speed of 1200 frames/s. A dual-mode CMOS ISFET sensor with suppressed FPN for accurate large-arrayed pH sensing is proposed and demonstrated with state-of-the-art measured results toward accurate and high-throughput DNA sequencing. The developed dual-mode CMOS ISFET sensor has great potential for future personal genome diagnostics with high accuracy and low cost.

  13. The exercise and affect relationship: evidence for the dual-mode model and a modified opponent process theory.

    Science.gov (United States)

    Markowitz, Sarah M; Arent, Shawn M

    2010-10-01

    This study examined the relationship between exertion level and affect using the framework of opponent-process theory and the dual-mode model, with the Activation-Deactivation Adjective Checklist and the State Anxiety Inventory among 14 active and 14 sedentary participants doing 20 min of treadmill exercise at speeds of 5% below, 5% above, and at lactate threshold (LT). We found a significant effect of time, condition, Time × Condition, and Time × Group, but no group, Group × Condition, or Time × Group × Condition effects, such that the 5% above LT condition produced a worsening of affect in-task compared with all other conditions whereas, across conditions, participants experienced in-task increases in energy and tension, and in-task decreases in tiredness and calmness relative to baseline. Posttask, participants experienced mood improvement (decreased tension, anxiety, and increased calmness) across conditions, with a 30-min delay in the above LT condition. These results partially support the dual-mode model and a modified opponent-process theory.

  14. In situ, dual-mode monitoring of organ-on-a-chip with smartphone-based fluorescence microscope.

    Science.gov (United States)

    Cho, Soohee; Islas-Robles, Argel; Nicolini, Ariana M; Monks, Terrence J; Yoon, Jeong-Yeol

    2016-12-15

    The use of organ-on-a-chip (OOC) platforms enables improved simulation of the human kidney's response to nephrotoxic drugs. The standard method of analyzing nephrotoxicity from existing OOC has majorly consisted of invasively collecting samples (cells, lysates, media, etc.) from an OOC. Such disruptive analyses potentiate contamination, disrupt the replicated in vivo environment, and require expertize to execute. Moreover, traditional analyses, including immunofluorescence microscopy, immunoblot, and microplate immunoassay are essentially not in situ and require substantial time, resources, and costs. In the present work, the incorporation of fluorescence nanoparticle immunocapture/immunoagglutination assay into an OOC enabled dual-mode monitoring of drug-induced nephrotoxicity in situ. A smartphone-based fluorescence microscope was fabricated as a handheld in situ monitoring device attached to an OOC. Both the presence of γ-glutamyl transpeptidase (GGT) on the apical brush-border membrane of 786-O proximal tubule cells within the OOC surface, and the release of GGT to the outflow of the OOC were evaluated with the fluorescence scatter detection of captured and immunoagglutinated anti-GGT conjugated nanoparticles. This dual-mode assay method provides a novel groundbreaking tool to enable the internal and external in situ monitoring of the OOC, which may be integrated into any existing OOCs to facilitate their subsequent analyses. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Terminalia Chebula provides protection against dual modes of necroptotic and apoptotic cell death upon death receptor ligation.

    Science.gov (United States)

    Lee, Yoonjung; Byun, Hee Sun; Seok, Jeong Ho; Park, Kyeong Ah; Won, Minho; Seo, Wonhyoung; Lee, So-Ra; Kang, Kidong; Sohn, Kyung-Cheol; Lee, Ill Young; Kim, Hyeong-Geug; Son, Chang Gue; Shen, Han-Ming; Hur, Gang Min

    2016-04-27

    Death receptor (DR) ligation elicits two different modes of cell death (necroptosis and apoptosis) depending on the cellular context. By screening a plant extract library from cells undergoing necroptosis or apoptosis, we identified a water extract of Terminalia chebula (WETC) as a novel and potent dual inhibitor of DR-mediated cell death. Investigation of the underlying mechanisms of its anti-necroptotic and anti-apoptotic action revealed that WETC or its constituents (e.g., gallic acid) protected against tumor necrosis factor-induced necroptosis via the suppression of TNF-induced ROS without affecting the upstream signaling events. Surprisingly, WETC also provided protection against DR-mediated apoptosis by inhibition of the caspase cascade. Furthermore, it activated the autophagy pathway via suppression of mTOR. Of the WETC constituents, punicalagin and geraniin appeared to possess the most potent anti-apoptotic and autophagy activation effect. Importantly, blockage of autophagy with pharmacological inhibitors or genetic silencing of Atg5 selectively abolished the anti-apoptotic function of WETC. These results suggest that WETC protects against dual modes of cell death upon DR ligation. Therefore, WETC might serve as a potential treatment for diseases characterized by aberrantly sensitized apoptotic or non-apoptotic signaling cascades.

  16. Giant Gold Nanowire Vesicle-Based Colorimetric and SERS Dual-Mode Immunosensor for Ultrasensitive Detection of Vibrio parahemolyticus.

    Science.gov (United States)

    Guo, Zhiyong; Jia, Yaru; Song, Xinxin; Lu, Jing; Lu, Xuefei; Liu, Baoqing; Han, Jiaojiao; Huang, Youju; Zhang, Jiawei; Chen, Tao

    2018-05-15

    Conventional methods for the detection of Vibrio parahemolyticus (VP) usually need tedious, labor-intensive processes, and have low sensitivity, which further limits their practical applications. Herein, we developed a simple and efficient colorimetry and surface-enhanced Raman scattering (SERS) dual-mode immunosensor for sensitive detection of VP, by employing giant Au vesicles with anchored tiny gold nanowires (AuNW) as a smart probe. Due to the larger specific surface and special hollow structure of giant Au vesicles, silver staining would easily lead to vivid color change for colorimetric analysis and further amplify SERS signals. The t-test was further used to determine if two sets of data from colorimetry and SERS were significantly different from each other. The result shows that there was no significant difference between data from the two methods. Two sets of data can mutually validate each other and avoid false positive and negative detection. The designed colorimetry-SERS dual-mode sensor would be very promising in various applications such as food safety inspection, personal healthcare, and on-site environmental monitoring.

  17. Novel control modes to improve the performance of rectilinear ion trap mass spectrometer with dual pressure chambers

    Science.gov (United States)

    Huo, Xinming; Tang, Fei; Zhang, Xiaohua; Chen, Jin; Zhang, Yan; Guo, Cheng'an; Wang, Xiaohao

    2016-10-01

    The rectilinear ion trap (RIT) has gradually become one of the preferred mass analyzers for portable mass spectrometers because of its simple configuration. In order to enhance the performance, including sensitivity, quantitation capability, throughput, and resolution, a novel RIT mass spectrometer with dual pressure chambers was designed and characterized. The studied system constituted a quadrupole linear ion trap (QLIT) in the first chamber and a RIT in the second chamber. Two control modes are hereby proposed: Storage Quadrupole Linear Ion Trap-Rectilinear Ion Trap (SQLIT-RIT) mode, in which the QLIT was used at high pressure for ion storage and isolation, and the RIT was used for analysis; and Analysis Quadrupole Linear Ion Trap-Rectilinear Ion Trap (AQLIT-RIT) mode, in which the QLIT was used for ion storage and cooling. Subsequently, synchronous scanning and analysis were carried out by QLIT and RIT. In SQLIT-RIT mode, signal intensity was improved by a factor of 30; the limit of quantitation was reduced more than tenfold to 50 ng mL-1, and an optimal duty cycle of 96.4% was achieved. In AQLIT-RIT mode, the number of ions coexisting in the RIT was reduced, which weakened the space-charge effect and reduced the mass shift. Furthermore, the mass resolution was enhanced by a factor of 3. The results indicate that the novel control modes achieve satisfactory performance without adding any system complexity, which provides a viable pathway to guarantee good analytical performance in miniaturization of the mass spectrometer.

  18. 2-D modeling of dual-mode acoustic phonon excitation of a triangular nanoplate

    International Nuclear Information System (INIS)

    Tai, Po-Tse; Yu, Pyng; Tang, Jau

    2010-01-01

    Graphical abstract: Modeling the lattice dynamics of a triangular plate with the arrows indicating the direction of impulsive thermal stress. We investigated ultrafast structural dynamics of triangular nanoplates based on 2-D Fermi-Pasta-Ulam model to explain coherent acoustic phonon excitation in nanoprisms. - Abstract: In this theoretical work, we investigated coherent phonon excitation of a triangular nanoplate based on 2-D Fermi-Pasta-Ulam lattice model. Based on the two-temperature model commonly used in description of laser heating of metals, we considered two kinds of forces related to electronic and lattice stresses. Based on extensive simulation and analysis, we identified two major planar phonon modes, namely, a standing wave mode related to the triangle bisector and another mode corresponding to half of the side length. This work elucidates the roles of laser-induced electronic stress and lattice stress in controlling the initial phase and the amplitude ratio between these two phonon modes.

  19. A tuneable, power efficient and narrow single longitudinal mode fibre ring laser using an inline dual-taper fibre Mach–Zehnder filter

    International Nuclear Information System (INIS)

    Ahmad, H; Dernaika, M; Alimadad, M; Ibrahim, M F; Lim, K S; Harun, S W; Kharraz, O M

    2014-01-01

    A tuneable single longitudinal mode fibre ring laser with dual-taper fibre filter is proposed and experimentally demonstrated in this paper. The single longitudinal mode operation, and power limitations for a Mach–Zehnder interferometer filter generated from a single mode fibre, are verified for the first time. Incorporating an in-line taper fibre Mach–Zehnder interferometer filter inside the laser ring cavity causes a spatial mode beating interference, resulting in a passive narrow band filter with the ability to generate stable single longitudinal modes. The single longitudinal mode achieves a side mode suppression ratio of more than 60 dB using low pump power. The tuneability of the fibre laser ranges from 1525 to 1562 nm using a passive band pass filter. A study of the stability and limitation of the single longitudinal mode in the Mach–Zehnder tapered fibre is also presented. (paper)

  20. Dual-Mode Gas Sensor Composed of a Silicon Nanoribbon Field Effect Transistor and a Bulk Acoustic Wave Resonator: A Case Study in Freons

    Directory of Open Access Journals (Sweden)

    Ye Chang

    2018-01-01

    Full Text Available In this paper, we develop a novel dual-mode gas sensor system which comprises a silicon nanoribbon field effect transistor (Si-NR FET and a film bulk acoustic resonator (FBAR. We investigate their sensing characteristics using polar and nonpolar organic compounds, and demonstrate that polarity has a significant effect on the response of the Si-NR FET sensor, and only a minor effect on the FBAR sensor. In this dual-mode system, qualitative discrimination can be achieved by analyzing polarity with the Si-NR FET and quantitative concentration information can be obtained using a polymer-coated FBAR with a detection limit at the ppm level. The complementary performance of the sensing elements provides higher analytical efficiency. Additionally, a dual mixture of two types of freons (CFC-113 and HCFC-141b is further analyzed with the dual-mode gas sensor. Owing to the small size and complementary metal-oxide semiconductor (CMOS-compatibility of the system, the dual-mode gas sensor shows potential as a portable integrated sensing system for the analysis of gas mixtures in the future.

  1. Failure mode and effects analysis in a dual-product microsphere brachytherapy environment.

    Science.gov (United States)

    Younge, Kelly Cooper; Lee, Choonik; Moran, Jean M; Feng, Mary; Novelli, Paula; Prisciandaro, Joann I

    We performed a failure mode and effects analysis (FMEA) during the addition of a new microspheres product into our existing microsphere brachytherapy program to identify areas for safety improvements. A diverse group of team members from the microsphere program participated in the project to create a process map, identify and score failure modes, and discuss programmatic changes to address the highest ranking items. We developed custom severity ranking scales for staff- and institution-related failure modes to encompass possible risks that may exist outside of patient-based effects. Between both types of microsphere products, 173 failure mode/effect pairs were identified: 90 for patients, 35 for staff, and 48 for the institution. The SIR-Spheres program was ranked separately from the TheraSphere program because of significant differences in workflow during dose calculation, preparation, and delivery. High-ranking failure modes in each category were addressed with programmatic changes. The FMEA aided in identifying potential risk factors in our microsphere program and allowed a theoretically safer and more efficient design of the workflow and quality assurance for both our new SIR-Spheres program and our existing TheraSphere program. As new guidelines are made available, and our experience with the SIR-Spheres program increases, we will update the FMEA as an efficient starting point for future improvements. Copyright © 2016 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

  2. Development of a micromechanical pitch-tunable grating with reflective/transmissive dual working modes

    International Nuclear Information System (INIS)

    Yu, Yi-Ting; Yuan, Wei-Zheng; Li, Tai-Ping; Yan, Bin

    2010-01-01

    In this paper, a micromechanical pitch-tunable grating with the capability of working in both reflective and transmissive modes is developed by using the silicon-on-glass (SOG) process. At a voltage of 65 V, the grating period is measured to increase by 4.62%. A simple optical experiment is performed to demonstrate how the proposed grating works in both modes. Then, experiments to measure the change of the diffraction angle versus driving voltage in both reflective and transmissive modes are designed and carried out utilizing an area-arrayed charge-coupled device (CCD), and the results are in good agreement with the theoretical calculation. Discussions on the structural configuration and diffraction efficiency of the proposed grating are presented. The grating presented provides better flexibility in the design and development of application systems.

  3. Compact Microstrip Triple-Mode Bandpass Filters Using Dual-Stub-Loaded Spiral Resonators

    Directory of Open Access Journals (Sweden)

    K. D. Xu

    2017-04-01

    Full Text Available Two new microstrip triple-mode resonators loaded with T-shaped open stubs using axially and centrally symmetric spiral structures, respectively, are presented. Spiraled for circuit size reduction, these two half-wavelength resonators can both generate three resonant modes over a wide frequency band by loading two T-stubs with different lengths. Due to the structural symmetry, they can be analyzed by odd- and even-mode method. To validate the design concept, two compact bandpass filters (BPFs using these two novel resonators with center frequencies of 1.76 GHz and 2.44 GHz for the GSM1800 and WLAN/Zigbee applications, respectively, have been designed, fabricated and tested. The center frequencies and bandwidths can be tunable through the analysis of resonant frequency responses, fractional bandwidths and external quality factor versus the resonator parameters. The final measured results have achieved good consistence with the simulations of these two BPFs.

  4. Dual mode linguistic hedge fuzzy logic controller for an isolated wind-diesel hybrid power system with superconducting magnetic energy storage unit

    International Nuclear Information System (INIS)

    Thameem Ansari, M.Md.; Velusami, S.

    2010-01-01

    A design of dual mode linguistic hedge fuzzy logic controller for an isolated wind-diesel hybrid power system with superconducting magnetic energy storage unit is proposed in this paper. The design methodology of dual mode linguistic hedge fuzzy logic controller is a hybrid model based on the concepts of linguistic hedges and hybrid genetic algorithm-simulated annealing algorithms. The linguistic hedge operators are used to adjust the shape of the system membership functions dynamically and can speed up the control result to fit the system demand. The hybrid genetic algorithm-simulated annealing algorithm is adopted to search the optimal linguistic hedge combination in the linguistic hedge module. Dual mode concept is also incorporated in the proposed controller because it can improve the system performance. The system with the proposed controller was simulated and the frequency deviation resulting from a step load disturbance is presented. The comparison of the proportional plus integral controller, fuzzy logic controller and the proposed dual mode linguistic hedge fuzzy logic controller shows that, with the application of the proposed controller, the system performance is improved significantly. The proposed controller is also found to be less sensitive to the changes in the parameters of the system and also robust under different operating modes of the hybrid power system.

  5. Development and Operation of Dual-Mode Analyzers for Wireless Power Consortium/Power Matters Alliance Wireless Power Systems.

    Science.gov (United States)

    Um, Keehong

    2016-05-01

    We have designed a protocol analyzer to be used in wireless power systems and analyzed the operation of wireless chargers defined by standards of Qi of Wireless Power Consortium (WPC) and Power Matters Alliance (PMA) protocols. The integrated circuit (IC, or microchip) developed so far for wireless power transmission is not easily adopted by chargers for specific purposes. A device for measuring the performance of test equipment currently available is required to transform and expand the types of protocol. Since a protocol analyzer with these functions is required, we have developed a device that can analyze the two protocols of WPC and PMA at the same time. As a result of our research, we present a dual-mode system that can analyze the protocols of both WPC and PMA.

  6. Ultrafast spectral dynamics of dual-color-soliton intracavity collision in a mode-locked fiber laser

    Science.gov (United States)

    Wei, Yuan; Li, Bowen; Wei, Xiaoming; Yu, Ying; Wong, Kenneth K. Y.

    2018-02-01

    The single-shot spectral dynamics of dual-color-soliton collisions inside a mode-locked laser is experimentally and numerically investigated. By using the all-optically dispersive Fourier transform, we spectrally unveil the collision-induced soliton self-reshaping process, which features dynamic spectral fringes over the soliton main lobe, and the rebuilding of Kelly sidebands with wavelength drifting. Meanwhile, the numerical simulations validate the experimental observation and provide additional insights into the physical mechanism of the collision-induced spectral dynamics from the temporal domain perspective. It is verified that the dynamic interference between the soliton and the dispersive waves is responsible for the observed collision-induced spectral evolution. These dynamic phenomena not only demonstrate the role of dispersive waves in the sophisticated soliton interaction inside the laser cavity, but also facilitate a deeper understanding of the soliton's inherent stability.

  7. Development of an Advanced Digital Reactor Protection System Using Diverse Dual Processors to Prevent Common-Mode Failure

    International Nuclear Information System (INIS)

    Shin, Hyun Kook; Nam, Sang Ku; Sohn, Se Do; Chang, Hoon Seon

    2003-01-01

    The advanced digital reactor protection system (ADRPS) with diverse dual processors has been developed to prevent common-mode failure (CMF). The principle of diversity is applied to both hardware design and software design. For hardware diversity, two different types of CPUs are used for the bistable processor and local coincidence logic (LCL) processor. The Versa Module Eurocard-based single board computers are used for the CPU hardware platforms. The QNX operating system and the VxWorks operating system were selected for software diversity. Functional diversity is also applied to the input and output modules, and to the algorithm in the bistable processors and LCL processors. The characteristics of the newly developed digital protection system are described together with the preventive capability against CMF. Also, system reliability analysis is discussed. The evaluation results show that the ADRPS has a good preventive capability against the CMF and is a highly reliable reactor protection system

  8. Design of a search and rescue terminal based on the dual-mode satellite and CDMA network

    Science.gov (United States)

    Zhao, Junping; Zhang, Xuan; Zheng, Bing; Zhou, Yubin; Song, Hao; Song, Wei; Zhang, Meikui; Liu, Tongze; Zhou, Li

    2010-12-01

    The current goal is to create a set of portable terminals with GPS/BD2 dual-mode satellite positioning, vital signs monitoring and wireless transmission functions. The terminal depends on an ARM processor to collect and combine data related to vital signs and GPS/BD2 location information, and sends the message to headquarters through the military CDMA network. It integrates multiple functions as a whole. The satellite positioning and wireless transmission capabilities are integrated into the motherboard, and the vital signs sensors used in the form of belts communicate with the board through Bluetooth. It can be adjusted according to the headquarters' instructions. This kind of device is of great practical significance for operations during disaster relief, search and rescue of the wounded in wartime, non-war military operations and other special circumstances.

  9. Software verification and validation methodology for advanced digital reactor protection system using diverse dual processors to prevent common mode failure

    International Nuclear Information System (INIS)

    Son, Ki Chang; Shin, Hyun Kook; Lee, Nam Hoon; Baek, Seung Min; Kim, Hang Bae

    2001-01-01

    The Advanced Digital Reactor Protection System (ADRPS) with diverse dual processors is being developed by the National Research Lab of KOPEC for ADRPS development. One of the ADRPS goals is to develop digital Plant Protection System (PPS) free of Common Mode Failure (CMF). To prevent CMF, the principle of diversity is applied to both hardware design and software design. For the hardware diversity, two different types of CPUs are used for Bistable Processor and Local Coincidence Logic Processor. The VME based Single Board Computers (SBC) are used for the CPU hardware platforms. The QNX Operating System (OS) and the VxWorks OS are used for software diversity. Rigorous Software Verification and Validation (V and V) is also required to prevent CMF. In this paper, software V and V methodology for the ADRPS is described to enhance the ADRPS software reliability and to assure high quality of the ADRPS software

  10. Dual source multidetector CT-angiography before transcatheter aortic valve implantation (TAVI) using a high-pitch spiral acquisition mode

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, W.; Anders, K.; May, M.S.; Uder, M. [University of Erlangen, Department of Radiology, Erlangen (Germany); Schuhbaeck, A.; Gauss, S.; Marwan, M.; Arnold, M.; Muschiol, G.; Daniel, W.G.; Achenbach, S. [University of Erlangen, Department of Cardiology, Erlangen (Germany); Ensminger, S. [University of Erlangen, Department of Cardiac Surgery, Erlangen (Germany)

    2012-01-15

    Transcatheter Aortic Valve Implantation (TAVI) is an alternative to surgical valve replacement in high risk patients. Angiography of the aortic root, aorta and iliac arteries is required to select suitable candidates, but contrast agents can be harmful due to impaired renal function. We evaluated ECG-triggered high-pitch spiral dual source Computed Tomography (CT) with minimized volume of contrast agent to assess aortic root anatomy and vascular access. 42 patients (82 {+-} 6 years) scheduled for TAVI underwent dual source (DS) CT angiography (CTA) of the aorta using a prospectively ECG-triggered high-pitch spiral mode (pitch = 3.4) with 40 mL iodinated contrast agent. We analyzed aortic root/iliac dimensions, attenuation, contrast to noise ratio (CNR), image noise and radiation exposure. Aortic root/iliac dimensions and distance of coronary ostia from the annulus could be determined in all cases. Mean aortic and iliac artery attenuation was 320 {+-} 70 HU and 340 {+-} 77 HU. Aortic/iliac CNR was 21.7 {+-} 6.8 HU and 14.5 {+-} 5.4 HU using 100 kV (18.8 {+-} 4.1 HU and 8.7 {+-} 2.6 HU using 120 kV). Mean effective dose was 4.5 {+-} 1.2 mSv. High-pitch spiral DSCTA can be used to assess the entire aorta and iliac arteries in TAVI candidates with a low volume of contrast agent while preserving diagnostic image quality. (orig.)

  11. Observation of stable bound soliton with dual-wavelength in a passively mode-locked Er-doped fiber laser

    International Nuclear Information System (INIS)

    Zheng Yu; Tian Jin-Rong; Dong Zi-Kai; Xu Run-Qin; Li Ke-Xuan; Song Yan-Rong

    2017-01-01

    A phase-locked bound state soliton with dual-wavelength is observed experimentally in a passively mode-locked Er-doped fiber (EDF) laser with a fiber loop mirror (FLM). The pulse duration of the soliton is 15 ps and the peak-to-peak separation is 125 ps. The repetition rate of the pulse sequence is 3.47 MHz. The output power is 11.8 mW at the pump power of 128 mW, corresponding to the pulse energy of 1.52 nJ. The FLM with a polarization controller can produce a comb spectrum, which acts as a filter. By adjusting the polarization controller or varying the pump power, the central wavelength of the comb spectrum can be tuned. When it combines with the reflective spectrum of the fiber Bragg grating, the total spectrum of the cavity can be cleaved into two parts, then the bound state soliton with dual-wavelength at 1549.7 nm and 1550.4 nm is obtained. (paper)

  12. Development of Real-Time Dual-Display Handheld and Bench-Top Hybrid-Mode SD-OCTs

    Directory of Open Access Journals (Sweden)

    Nam Hyun Cho

    2014-01-01

    Full Text Available Development of a dual-display handheld optical coherence tomography (OCT system for retina and optic-nerve-head diagnosis beyond the volunteer motion constraints is reported. The developed system is portable and easily movable, containing the compact portable OCT system that includes the handheld probe and computer. Eye posterior chambers were diagnosed using the handheld probe, and the probe could be fixed to the bench-top cradle depending on the volunteers’ physical condition. The images obtained using this handheld probe were displayed in real time on the computer monitor and on a small secondary built-in monitor; the displayed images were saved using the handheld probe’s built-in button. Large-scale signal-processing procedures such as k-domain linearization, fast Fourier transform (FFT, and log-scaling signal processing can be rapidly applied using graphics-processing-unit (GPU accelerated processing rather than central-processing-unit (CPU processing. The Labview-based system resolution is 1,024 × 512 pixels, and the frame rate is 56 frames/s, useful for real-time display. The 3D images of the posterior chambers including the retina, optic-nerve head, blood vessels, and optic nerve were composed using real-time displayed images with 500 × 500 × 500 pixel resolution. A handheld and bench-top hybrid mode with a dual-display handheld OCT was developed to overcome the drawbacks of the conventional method.

  13. Dual-channel amplification in a single-mode diode laser for multi-isotope laser cooling

    International Nuclear Information System (INIS)

    Booth, James L.; Van Dongen, Janelle; Lebel, Paul; Klappauf, Bruce G.; Madison, Kirk W.

    2007-01-01

    The output from two grating-stabilized external-cavity diode lasers were injected into a single-mode diode laser. Operating at a wavelength of 780 nm, this laser produced ∼50 mW of power with two main frequency components of the same spectral characteristics of the seed lasers. The power ratio of the amplified components was freely adjustable due to gain saturation, and amplification was observed for frequency differences of the two seed lasers in the range from 73 MHz to 6.6 GHz. This system was used to realize a dual isotope magneto-optic trap (MOT) for rubidium ( 85 Rb and 87 Rb). The resulting position and cloud size of the dual isotope MOT was the same as that of the single species MOTs to within ±10 and ±20 μm, respectively. We also characterized the additional spectral components produced by four wave mixing (FWM) in the diode laser amplifier and utilized a particular FWM sideband to realize hyperfine pumping and subsequent laser trapping of 85 Rb in the absence of a 'repump' laser dedicated to hyperfine pumping

  14. Bend-insensitive single-mode photonic crystal fiber with ultralarge effective area for dual applications

    Science.gov (United States)

    Islam, Md. Asiful; Alam, M. Shah

    2013-05-01

    A novel photonic crystal fiber (PCF) having circular arrangement of cladding air holes has been designed and numerically optimized to obtain a bend insensitive single mode fiber with large mode area for both wavelength division multiplexing (WDM) communication and fiber-to-the-home (FTTH) application. The bending loss of the proposed bent PCF lies in the range of 10-3 to 10-4 dB/turn or lower over 1300 to 1700 nm, and 2 × 10-4 dB/turn at the wavelength of 1550 nm for a 30-mm bend radius with a higher order mode (HOM) cut-off frequency below 1200 nm for WDM application. When the whole structure of the PCF is scaled down, a bending loss of 6.78×10-4 dB/turn at 1550 nm for a 4-mm bend radius is obtained, and the loss remains in the order of 10-4 dB/turn over the same range of wavelength with an HOM cut-off frequency below 700 nm, and makes the fiber useful for FTTH applications. Furthermore, this structure is also optimized to show a splice loss near zero for fusion-splicing to a conventional single-mode fiber (SMF).

  15. Animacroxam, a Novel Dual-Mode Compound Targeting Histone Deacetylases and Cytoskeletal Integrity of Testicular Germ Cell Cancer Cells.

    Science.gov (United States)

    Steinemann, Gustav; Dittmer, Alexandra; Kuzyniak, Weronika; Hoffmann, Björn; Schrader, Mark; Schobert, Rainer; Biersack, Bernhard; Nitzsche, Bianca; Höpfner, Michael

    2017-11-01

    Novel approaches for the medical treatment of advanced solid tumors, including testicular germ cell tumors (TGCT), are desperately needed. Especially, TGCT patients not responding to cisplatin-based therapy need therapeutic alternatives, as there is no effective medical treatment available for this particular subgroup. Here, we studied the suitability of the novel dual-mode compound animacroxam for TGCT treatment. Animacroxam consists of an HDAC-inhibitory hydroxamate moiety coupled to a 4,5-diarylimidazole with inherent cytoskeleton disrupting potency. Animacroxam revealed pronounced antiproliferative, cell-cycle arresting, and apoptosis-inducing effects in TGCT cell lines with different cisplatin sensitivities. The IC 50 values of animacroxam ranged from 0.22 to 0.42 μmol/L and were not correlated to the cisplatin sensitivity of the tumor cells. No unspecific cytotoxicity of animacroxam was observed in either cisplatin-sensitive or resistant TGCT cells, even at doses as high as 10 μmol/L. Furthermore, animacroxam induced the formation of actin stress fibers in cancer cells, thereby confirming the cytoskeleton-disrupting and antimigratory properties of its imidazole moiety. When compared with the clinically established HDAC inhibitor vorinostat, the novel dual-mode compound animacroxam exhibited superior antitumoral efficacy in vitro Animacroxam also reduced the tumor size of TGCT tumors in vivo , as evidenced by performing xenograft experiments on tumor bearing chorioallantoic membranes of fertilizes chicken eggs (CAM assay). The in vivo experiments also revealed a very good tolerability of the compound, and hence, animacroxam may be a promising candidate for innovative treatment of TGCT in general and the more so for platinum-insensitive or refractory TGCT. Mol Cancer Ther; 16(11); 2364-74. ©2017 AACR . ©2017 American Association for Cancer Research.

  16. Inverted Planar Perovskite Solar Cells with a High Fill Factor and Negligible Hysteresis by the Dual Effect of NaCl-Doped PEDOT:PSS.

    Science.gov (United States)

    Hu, Lijun; Sun, Kuan; Wang, Ming; Chen, Wei; Yang, Bo; Fu, Jiehao; Xiong, Zhuang; Li, Xinyi; Tang, Xiaosheng; Zang, Zhigang; Zhang, Shupeng; Sun, Lidong; Li, Meng

    2017-12-20

    The performance of inverted perovskite solar cells is highly dependent on hole extraction and surface properties of hole transport layers. To highlight the important role of hole transport layers, a facile and simple method is developed by adding sodium chloride (NaCl) into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The average power conversion efficiency of the perovskite solar cells prepared on NaCl-doped PEDOT:PSS is 17.1% with negligible hysteresis, compared favorably to the control devices (15.1%). Particularly, they exhibit markedly improved V oc and fill factor (FF), with the best FF as high as 81.9%. The enhancement of photovoltaic performance is ascribed to two effects. Better conductivity and hole extraction of PEDOT:PSS are observed after NaCl doping. More intriguingly, the perovskite polycrystalline film shows a preferred orientation along the (001) direction on NaCl-doped PEDOT:PSS, leading to a more uniform thin film. The comparison of the crystal structure between NaCl and MAPbCl 3 indicates a lattice constant mismatch less than 2% and a matched chlorine atom arrangement on the (001) surface, which implies that the NaCl crystallites on the top surface of PEDOT:PSS might serve as seeds guiding the growth of perovskite crystals. This simple method is fully compatible with printing technologies to mass-produce perovskite solar cells with high efficiency and tunable crystal orientations.

  17. Dual representation of item positions in verbal short-term memory: Evidence for two access modes.

    Science.gov (United States)

    Lange, Elke B; Verhaeghen, Paul; Cerella, John

    Memory sets of N = 1~5 digits were exposed sequentially from left-to-right across the screen, followed by N recognition probes. Probes had to be compared to memory list items on identity only (Sternberg task) or conditional on list position. Positions were probed randomly or in left-to-right order. Search functions related probe response times to set size. Random probing led to ramped, "Sternbergian" functions whose intercepts were elevated by the location requirement. Sequential probing led to flat search functions-fast responses unaffected by set size. These results suggested that items in STM could be accessed either by a slow search-on-identity followed by recovery of an associated location tag, or in a single step by following item-to-item links in study order. It is argued that this dual coding of location information occurs spontaneously at study, and that either code can be utilised at retrieval depending on test demands.

  18. Age Differences in Dual Information-Processing Modes: Implications for Cancer Decision Making

    Science.gov (United States)

    Peters, Ellen; Diefenbach, Michael A.; Hess, Thomas M.; Västfjäll, Daniel

    2008-01-01

    Age differences in affective/experiential and deliberative processes have important theoretical implications for cancer decision making as cancer is often a disease of older adulthood. We examine evidence for adult age differences in affective and deliberative information processes, review the sparse evidence about age differences in decision making and introduce how dual process theories and their findings might be applied to cancer decision making. Age-related declines in the efficiency of deliberative processes predict poorer-quality decisions as we age, particularly when decisions are unfamiliar and the information is numeric. However, age-related adaptive processes, including an increased focus on emotional goals and greater experience, can influence decision making and potentially offset age-related declines. A better understanding of the mechanisms that underlie cancer decision processes in our aging population should ultimately allow us to help older adults to better help themselves. PMID:19058148

  19. Age differences in dual information-processing modes: implications for cancer decision making.

    Science.gov (United States)

    Peters, Ellen; Diefenbach, Michael A; Hess, Thomas M; Västfjäll, Daniel

    2008-12-15

    Age differences in affective/experiential and deliberative processes have important theoretical implications for cancer decision making, as cancer is often a disease of older adulthood. The authors examined evidence for adult age differences in affective and deliberative information processes, reviewed the sparse evidence about age differences in decision making, and introduced how dual process theories and their findings might be applied to cancer decision making. Age-related declines in the efficiency of deliberative processes predict poorer-quality decisions as we age, particularly when decisions are unfamiliar and the information is numeric. However, age-related adaptive processes, including an increased focus on emotional goals and greater experience, can influence decision making and potentially offset age-related declines. A better understanding of the mechanisms that underlie cancer decision processes in our aging population should ultimately allow us to help older adults to better help themselves.

  20. Experimental Lamb mode identification in a plate containing a hole using dual signal processing

    International Nuclear Information System (INIS)

    Grondel, Sébastien; Assaad, Jamal; Youbi, Faysal El; Moulin, Emmanuel; Leyla, Najib Abou

    2008-01-01

    The identification of Lamb mode amplitude variation as a function of the damage evolution is still the most difficult step in the process of damage monitoring using embedded Lamb wave-based systems. The aim of this paper is to propose a simple system based on the generation of two different frequencies in order to better identify Lamb mode amplitude and to avoid false data interpretation in plates containing a hole of variable diameter. This identification is based on a simple relation between the short-time Fourier transform and the two-dimensional Fourier transform. Experimentally, a 3 mm thick aluminium plate is used and the two frequencies have been chosen equal to 400 kHz and 600 kHz in order to generate the two first fundamental Lamb waves

  1. Effect of engine load and biogas flow rate to the performance of a compression ignition engine run in dual-fuel (dieselbiogas) mode

    Science.gov (United States)

    Ambarita, H.

    2018-02-01

    The Government of Indonesia (GoI) has released a target on reduction Green Houses Gases emissions (GHG) by 26% from level business-as-usual by 2020, and the target can be up to 41% by international supports. In the energy sector, this target can be reached effectively by promoting fossil fuel replacement or blending with biofuel. One of the potential solutions is operating compression ignition (CI) engine in dual-fuel (diesel-biogas) mode. In this study effects of engine load and biogas flow rate on the performance and exhaust gas emissions of a compression ignition engine run in dual-fuel mode are investigated. In the present study, the used biogas is refined with methane content 70% of volume. The objectives are to explore the optimum operating condition of the CI engine run in dual-fuel mode. The experiments are performed on a four-strokes CI engine with rated output power of 4.41 kW. The engine is tested at constant speed 1500 rpm. The engine load varied from 600W to 1500W and biogas flow rate varied from 0 L/min to 6 L/min. The results show brake thermal efficiency of the engine run in dual-fuel mode is better than pure diesel mode if the biogas flow rates are 2 L/min and 4 L/min. It is recommended to operate the present engine in a dual-fuel mode with biogas flow rate of 4 L/min. The consumption of diesel fuel can be replaced up to 50%.

  2. Inverter for Interchangeable Use as Current Source Inverter and Voltage Source Inverter for Interconnecting to Grid

    Science.gov (United States)

    Teruya, Daisuke; Masukawa, Shigeo; Iida, Shoji

    We propose a novel inverter that can be operated either as a Current Source Inverter (CSI) or as a Voltage Source Inverter (VSI) by changing only the control signals. It is proper to apply it to the interconnecting system with renewal energy, such as photovoltaic cells or wind generation systems, to a grid. This inverter is usually operated as the CSI connected to the grid. Even if the energy source has a lower voltage than the grid, the energy can be supplied to the grid through the proposed inverter. The power factor can be briefly maintained at almost unity. When power supply from the grid is interrupted, the proposed circuit should be operated as the VSI in the stand-alone operation mode. In this way, the circuit can maintain a constant output voltage to the loads. In this paper, the proposed circuit configuration and the control schemes for both the CSI and the VSI are described. Further, the circuit characteristics for both are discussed experimentally.

  3. Dual Mode Sensing with Low-Profile Piezoelectric Thin Wafer Sensors for Steel Bridge Crack Detection and Diagnosis

    Directory of Open Access Journals (Sweden)

    Lingyu Yu

    2012-01-01

    Full Text Available Monitoring of fatigue cracking in steel bridges is of high interest to many bridge owners and agencies. Due to the variety of deterioration sources and locations of bridge defects, there is currently no single method that can detect and address the potential sources globally. In this paper, we presented a dual mode sensing methodology integrating acoustic emission and ultrasonic wave inspection based on the use of low-profile piezoelectric wafer active sensors (PWAS. After introducing the research background and piezoelectric sensing principles, PWAS crack detection in passive acoustic emission mode is first presented. Their acoustic emission detection capability has been validated through both static and compact tension fatigue tests. With the use of coaxial cable wiring, PWAS AE signal quality has been improved. The active ultrasonic inspection is conducted by the damage index and wave imaging approach. The results in the paper show that such an integration of passive acoustic emission detection with active ultrasonic sensing is a technological leap forward from the current practice of periodic and subjective visual inspection and bridge management based primarily on history of past performance.

  4. An effort to enhance hydrogen energy share in a compression ignition engine under dual-fuel mode using low temperature combustion strategies

    International Nuclear Information System (INIS)

    Chintala, V.; Subramanian, K.A.

    2015-01-01

    Highlights: • H 2 energy share increased from 18% with DDM to 36% with WDM (water injection). • H 2 energy share improved marginally with retarded injection timing mode (RDM). • Energy efficiency increased with increasing amount of H 2 in dual-fuel engine. • NO x emission decreased with water injection and retarded pilot fuel injection. • HC, CO and smoke emissions increased slightly with low temperature combustion. - Abstract: A limited hydrogen (H 2 ) energy share due to knocking is the major hurdle for effective utilization of H 2 in compression ignition (CI) engines under dual-fuel operation. The present study aims at improvement of H 2 energy share in a 7.4 kW direct injection CI engine under dual-fuel mode with two low temperature combustion (LTC) strategies; (i) retarded pilot fuel injection timing and (ii) water injection. Experiments were carried out under conventional strategies of diesel dual-fuel mode (DDM) and B20 dual-fuel mode (BDM); and LTC strategies of retarded injection timing dual-fuel mode (RDM) and water injected dual-fuel mode (WDM). The results explored that the H 2 energy share increased significantly from 18% with conventional DDM to 24, and 36% with RDM, and WDM respectively. The energy efficiency increased with increasing H 2 energy share under dual-fuel operation; however, for a particular energy share of 18% H 2 , it decreased from 34.8% with DDM to 33.7% with BDM, 32.7% with WDM and 29.9% with RDM. At 18% H 2 energy share, oxides of nitrogen emission decreased by 37% with RDM and 32% with WDM as compared to conventional DDM due to reduction of in-cylinder temperature, while it increased slightly about 5% with BDM. It is emerged from the study that water injection technique is the viable option among all other strategies to enhance the H 2 energy share in the engine with a slight penalty of increase in smoke, hydrocarbon, and carbon monoxide emissions

  5. A dual-mode mobile phone microscope using the onboard camera flash and ambient light.

    Science.gov (United States)

    Orth, A; Wilson, E R; Thompson, J G; Gibson, B C

    2018-02-19

    Mobile phone microscopes are a natural platform for point-of-care imaging, but current solutions require an externally powered illumination source, thereby adding bulk and cost. We present a mobile phone microscope that uses the internal flash or sunlight as the illumination source, thereby reducing complexity whilst maintaining functionality and performance. The microscope is capable of both brightfield and darkfield imaging modes, enabling microscopic visualisation of samples ranging from plant to mammalian cells. We describe the microscope design principles, assembly process, and demonstrate its imaging capabilities through the visualisation of unlabelled cell nuclei to observing the motility of cattle sperm and zooplankton.

  6. Pitch ranking, electrode discrimination, and physiological spread-of-excitation using Cochlear's dual-electrode mode.

    Science.gov (United States)

    Goehring, Jenny L; Neff, Donna L; Baudhuin, Jacquelyn L; Hughes, Michelle L

    2014-08-01

    This study compared pitch ranking, electrode discrimination, and electrically evoked compound action potential (ECAP) spatial excitation patterns for adjacent physical electrodes (PEs) and the corresponding dual electrodes (DEs) for newer-generation Cochlear devices (Cochlear Ltd., Macquarie, New South Wales, Australia). The first goal was to determine whether pitch ranking and electrode discrimination yield similar outcomes for PEs and DEs. The second goal was to determine if the amount of spatial separation among ECAP excitation patterns (separation index, Σ) between adjacent PEs and the PE-DE pairs can predict performance on the psychophysical tasks. Using non-adaptive procedures, 13 subjects completed pitch ranking and electrode discrimination for adjacent PEs and the corresponding PE-DE pairs (DE versus each flanking PE) from the basal, middle, and apical electrode regions. Analysis of d' scores indicated that pitch-ranking and electrode-discrimination scores were not significantly different, but rather produced similar levels of performance. As expected, accuracy was significantly better for the PE-PE comparison than either PE-DE comparison. Correlations of the psychophysical versus ECAP Σ measures were positive; however, not all test/region correlations were significant across the array. Thus, the ECAP separation index is not sensitive enough to predict performance on behavioral tasks of pitch ranking or electrode discrimination for adjacent PEs or corresponding DEs.

  7. Dual-Mode Measurement and Theoretical Analysis of Evaporation Kinetics of Binary Mixtures

    Science.gov (United States)

    Song, Hanyu; He, Chi-Ruei; Basdeo, Carl; Li, Ji-Qin; Ye, Dezhuang; Kalonia, Devendra; Li, Si-Yu; Fan, Tai-Hsi

    Theoretical and experimental investigations are presented for the precision measurement of evaporation kinetics of binary mixtures using a quartz crystal resonator. A thin layer of light alcohol mixture including a volatile (methanol) and a much less volatile (1-butanol) components is deployed on top of the resonator. The normal or acoustic mode is to detect the moving liquid-vapor interface due to evaporation with a great spatial precision on the order of microns, and simultaneously the shear mode is used for in-situ detection of point viscosity or concentration of the mixture near the resonator. A one-dimensional theoretical model is developed to describe the underlying mass transfer and interfacial transport phenomena. Along with the modeling results, the transient evaporation kinetics, moving interface, and the stratification of viscosity of the liquid mixture during evaporation are simultaneously measured by the impedance response of the shear and longitudinal waves emitted from the resonator. The system can be used to characterize complicated evaporation kinetics involving multi-component fuels. American Chemical Society Petroleum Research Fund, NSF CMMI-0952646.

  8. Twin peak high-frequency quasi-periodic oscillations as a spectral imprint of dual oscillation modes of accretion tori

    Science.gov (United States)

    Bakala, P.; Goluchová, K.; Török, G.; Šrámková, E.; Abramowicz, M. A.; Vincent, F. H.; Mazur, G. P.

    2015-09-01

    Context. High-frequency (millisecond) quasi-periodic oscillations (HF QPOs) are observed in the X-ray power-density spectra of several microquasars and low-mass X-ray binaries. Two distinct QPO peaks, so-called twin peak QPOs, are often detected simultaneously exhibiting their frequency ratio close or equal to 3:2. A widely discussed class of proposed QPOs models is based on oscillations of accretion toroidal structures orbiting in the close vicinity of black holes or neutron stars. Aims: Following the analytic theory and previous studies of observable spectral signatures, we aim to model the twin peak QPOs as a spectral imprint of specific dual oscillation regime defined by a combination of the lowest radial and vertical oscillation mode of slender tori. We consider the model of an optically thick slender accretion torus with constant specific angular momentum. We examined power spectra and fluorescent Kα iron line profiles for two different simulation setups with the mode frequency relations corresponding to the epicyclic resonance HF QPOs model and modified relativistic precession QPOs model. Methods: We used relativistic ray-tracing implemented in the parallel simulation code LSDplus. In the background of the Kerr spacetime geometry, we analyzed the influence of the distant observer inclination and the spin of the central compact object. Relativistic optical projection of the oscillating slender torus is illustrated by images in false colours related to the frequency shift. Results: We show that performed simulations yield power spectra with the pair of dominant peaks that correspond to the frequencies of radial and vertical oscillation modes and with the peak frequency ratio equal to the proper value 3:2 on a wide range of inclinations and spin values. We also discuss exceptional cases of a very low and very high inclination, as well as unstable high spin relativistic precession-like configurations that predict a constant frequency ratio equal to 1:2. We

  9. Light curing through glass ceramics: effect of curing mode on micromechanical properties of dual-curing resin cements.

    Science.gov (United States)

    Flury, Simon; Lussi, Adrian; Hickel, Reinhard; Ilie, Nicoleta

    2014-04-01

    The aim of this study was to investigate micromechanical properties of five dual-curing resin cements after different curing modes including light curing through glass ceramic materials. Vickers hardness (VH) and indentation modulus (Y HU) of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA were measured after 1 week of storage (37 °C, 100 % humidity). The resin cements were tested following self-curing or light curing with the second-generation light-emitting diode (LED) curing unit Elipar FreeLight 2 in Standard Mode (1,545 mW/cm(2)) or with the third-generation LED curing unit VALO in High Power Mode (1,869 mW/cm(2)) or in XtraPower Mode (3,505 mW/cm(2)). Light curing was performed directly or through glass ceramic discs of 1.5 or 3 mm thickness of IPS Empress CAD or IPS e.max CAD. VH and Y HU were analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). RelyX Unicem 2 Automix resulted in the highest VH and Y HU followed by BeautiCem SA, BisCem, SpeedCEM, and finally Panavia F2.0. Self-curing of RelyX Unicem 2 Automix and SpeedCEM lowered VH and Y HU compared to light curing whereas self-curing of Panavia F2.0, BisCem, and BeautiCem SA led to similar or significantly higher VH and Y HU compared to light curing. Generally, direct light curing resulted in similar or lower VH and Y HU compared to light curing through 1.5-mm-thick ceramic discs. Light curing through 3-mm-thick discs of IPS e.max CAD generally reduced VH and Y HU for all resin cements except SpeedCEM, which was the least affected by light curing through ceramic discs. The resin cements responded heterogeneously to changes in curing mode. The applied irradiances and light curing times adequately cured the resin cements even through 1.5-mm-thick ceramic discs. When light curing resin cements through thick glass ceramic restorations, clinicians should consider to prolong the light curing times even with LED curing units providing high

  10. High voltage series resonant inverter ion engine screen supply. [SCR series resonant inverter for space applications

    Science.gov (United States)

    Biess, J. J.; Inouye, L. Y.; Shank, J. H.

    1974-01-01

    A high-voltage, high-power LC series resonant inverter using SCRs has been developed for an Ion Engine Power Processor. The inverter operates within 200-400Vdc with a maximum output power of 2.5kW. The inverter control logic, the screen supply electrical and mechanical characteristics, the efficiency and losses in power components, regulation on the dual feedback principle, the SCR waveforms and the component weight are analyzed. Efficiency of 90.5% and weight density of 4.1kg/kW are obtained.

  11. Integrated Inverter And Battery Charger

    Science.gov (United States)

    Rippel, Wally E.

    1988-01-01

    Circuit combines functions of dc-to-ac inversion (for driving ac motor in battery-powered vehicle) and ac-to-dc conversion (for charging battery from ac line when vehicle not in use). Automatically adapts to either mode. Design of integrated inverter/charger eliminates need for duplicate components, saves space, reduces weight and cost of vehicle. Advantages in other applications : load-leveling systems, standby ac power systems, and uninterruptible power supplies.

  12. Lipid characterization of individual porcine oocytes by dual mode DESI-MS and data fusion

    International Nuclear Information System (INIS)

    Pirro, Valentina; Oliveri, Paolo; Ferreira, Christina Ramires; González-Serrano, Andrés Felipe; Machaty, Zoltan; Cooks, Robert Graham

    2014-01-01

    Highlights: • Repeated analysis by DESI(±)-MS of intact single oocytes for lipid characterization. • Deployment of a data fusion strategy to merge positive and negative ion mode data. • Enhanced interpretation of metabolic changes by more efficient analysis of spectral data. • Discovery of increased fatty acid metabolism and membrane complexity during maturation. • Assistance in the improvement of in vitro embryo production for porcine species. - Abstract: The development of sensitive measurements to analyze individual cells is of relevance to elucidate specialized roles or metabolic functions of each cell under physiological and pathological conditions. Lipids play multiple and critical roles in cellular functions and the application of analytical methods in the lipidomics area is of increasing interest. In this work, in vitro maturation of porcine oocytes was studied. Two independent sources of chemical information (represented by mass spectra in the positive and negative ion modes) from single oocytes (immature oocytes, 24-h and 44-h in vitro matured oocytes) were acquired by using desorption electrospray ionization-mass spectrometry (DESI-MS). Low and mid-level data fusion strategies are presented with the aim of better exploring the large amount of chemical information contained in the two mass spectrometric lipid profiles. Data were explored by principal component analysis (PCA) within the two multi-block approaches to include information on free fatty acids, phospholipids, cholesterol-related molecules, di- and triacylglycerols. After data fusion, clearer differences among immature and in vitro matured porcine oocytes were observed, which provide novel information regarding lipid metabolism throughout oocyte maturation. In particular, changes in TAG composition, as well as increase in fatty acid metabolism and membrane complexity were evidenced during the in vitro maturation process. This information can assist the improvement of in vitro embryo

  13. Online Variable Topology-Type Photovoltaic Grid-Connected Inverter

    DEFF Research Database (Denmark)

    Wu, Fengjiang; Sun, Bo; Duan, Jiandong

    2015-01-01

    In photovoltaic (PV) grid-connected generation system, the key focus is how to expand the generation range of the PV array and enhance the total efficiency of the system. This paper originally derived expressions of the total loss and grid current total harmonics distortions of cascaded inverter...... and H-bridge inverter under the conditions of variable output voltage and power of the PV array. It is proved that, compared with the H-bridge inverter, the operation range of the cascaded inverter is wider, whereas the total loss is larger. Furthermore, a novel online variable topology-type grid......-connected inverter is proposed. A bidirectional power switch is introduced into the conventional cascaded inverter to connect the negative terminals of the PV arrays. When the output voltages of the PV arrays are lower, the proposed inverter works under cascaded inverter mode to obtain wider generation range. When...

  14. Integrated Inverter For Driving Multiple Electric Machines

    Science.gov (United States)

    Su, Gui-Jia [Knoxville, TN; Hsu, John S [Oak Ridge, TN

    2006-04-04

    An electric machine drive (50) has a plurality of inverters (50a, 50b) for controlling respective electric machines (57, 62), which may include a three-phase main traction machine (57) and two-phase accessory machines (62) in a hybrid or electric vehicle. The drive (50) has a common control section (53, 54) for controlling the plurality of inverters (50a, 50b) with only one microelectronic processor (54) for controlling the plurality of inverters (50a, 50b), only one gate driver circuit (53) for controlling conduction of semiconductor switches (S1-S10) in the plurality of inverters (50a, 50b), and also includes a common dc bus (70), a common dc bus filtering capacitor (C1) and a common dc bus voltage sensor (67). The electric machines (57, 62) may be synchronous machines, induction machines, or PM machines and may be operated in a motoring mode or a generating mode.

  15. Nonlinear defect localized modes and composite gray and anti-gray solitons in one-dimensional waveguide arrays with dual-flip defects

    Science.gov (United States)

    Liu, Yan; Guan, Yefeng; Li, Hai; Luo, Zhihuan; Mai, Zhijie

    2017-08-01

    We study families of stationary nonlinear localized modes and composite gray and anti-gray solitons in a one-dimensional linear waveguide array with dual phase-flip nonlinear point defects. Unstaggered fundamental and dipole bright modes are studied when the defect nonlinearity is self-focusing. For the fundamental modes, symmetric and asymmetric nonlinear modes are found. Their stable areas are studied using different defect coefficients and their total power. For the nonlinear dipole modes, the stability conditions of this type of mode are also identified by different defect coefficients and the total power. When the defect nonlinearity is replaced by the self-defocusing one, staggered fundamental and dipole bright modes are created. Finally, if we replace the linear waveguide with a full nonlinear waveguide, a new type of gray and anti-gray solitons, which are constructed by a kink and anti-kink pair, can be supported by such dual phase-flip defects. In contrast to the usual gray and anti-gray solitons formed by a single kink, their backgrounds on either side of the gray hole or bright hump have the same phase.

  16. Dual Mode NOx Sensor: Measuring Both the Accumulated Amount and Instantaneous Level at Low Concentrations

    Directory of Open Access Journals (Sweden)

    Jaco H. Visser

    2012-03-01

    Full Text Available The accumulating-type (or integrating-type NOx sensor principle offers two operation modes to measure low levels of NOx: The direct signal gives the total amount dosed over a time interval and its derivative the instantaneous concentration. With a linear sensor response, no baseline drift, and both response times and recovery times in the range of the gas exchange time of the test bench (5 to 7 s, the integrating sensor is well suited to reliably detect low levels of NOx. Experimental results are presented demonstrating the sensor’s integrating properties for the total amount detection and its sensitivity to both NO and to NO2. We also show the correlation between the derivative of the sensor signal and the known gas concentration. The long-term detection of NOx in the sub-ppm range (e.g., for air quality measurements is discussed. Additionally, a self-adaption of the measurement range taking advantage of the temperature dependency of the sensitivity is addressed.

  17. Micrococcus luteus mediated dual mode synthesis of gold nanoparticles: involvement of extracellular α-amylase and cell wall teichuronic acid.

    Science.gov (United States)

    Arunkumar, Pichaimani; Thanalakshmi, Muthukrishnan; Kumar, Priyadarsini; Premkumar, Kumpati

    2013-03-01

    In the present study we have utilized the bioreductive potential of Micrococcus luteus for the synthesis of gold nanoparticles. Biochemical and physiological analysis indicate that the biosynthesized GNPs were achieved by dual mode, involving extracellular α-amylase and cell wall teichuronic acid (TUA) of M. luteus. The biosynthetic potential of both α-amylase and TUA, after isolation from bacterium, was examined. Under optimum conditions, these biomolecules reduces Au(3+) into Au(0) and the resulting GNPs were found to be stable for 1 month. The synthesized GNPs were characterized by UV-VIS spectrometry, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). Results demonstrated that the synthesized GNPs were found to be monodispersive and spherical in shape with an average size of ∼6 nm and ∼50 nm for α-amylase and teichuronic acid, respectively. These findings suggest that M. luteus can be exploited as a potential biosource for the eco-friendly synthesis of gold nanoparticles. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Characterization of performance-emission indices of a diesel engine using ANFIS operating in dual-fuel mode with LPG

    Science.gov (United States)

    Chakraborty, Amitav; Roy, Sumit; Banerjee, Rahul

    2018-03-01

    This experimental work highlights the inherent capability of an adaptive-neuro fuzzy inference system (ANFIS) based model to act as a robust system identification tool (SIT) in prognosticating the performance and emission parameters of an existing diesel engine running of diesel-LPG dual fuel mode. The developed model proved its adeptness by successfully harnessing the effects of the input parameters of load, injection duration and LPG energy share on output parameters of BSFCEQ, BTE, NOX, SOOT, CO and HC. Successive evaluation of the ANFIS model, revealed high levels of resemblance with the already forecasted ANN results for the same input parameters and it was evident that similar to ANN, ANFIS also has the innate ability to act as a robust SIT. The ANFIS predicted data harmonized the experimental data with high overall accuracy. The correlation coefficient (R) values are stretched in between 0.99207 to 0.999988. The mean absolute percentage error (MAPE) tallies were recorded in the range of 0.02-0.173% with the root mean square errors (RMSE) in acceptable margins. Hence the developed model is capable of emulating the actual engine parameters with commendable ranges of accuracy, which in turn would act as a robust prediction platform in the future domains of optimization.

  19. A Priori Analysis of a Compressible Flamelet Model using RANS Data for a Dual-Mode Scramjet Combustor

    Science.gov (United States)

    Quinlan, Jesse R.; Drozda, Tomasz G.; McDaniel, James C.; Lacaze, Guilhem; Oefelein, Joseph

    2015-01-01

    In an effort to make large eddy simulation of hydrocarbon-fueled scramjet combustors more computationally accessible using realistic chemical reaction mechanisms, a compressible flamelet/progress variable (FPV) model was proposed that extends current FPV model formulations to high-speed, compressible flows. Development of this model relied on observations garnered from an a priori analysis of the Reynolds-Averaged Navier-Stokes (RANS) data obtained for the Hypersonic International Flight Research and Experimentation (HI-FiRE) dual-mode scramjet combustor. The RANS data were obtained using a reduced chemical mechanism for the combustion of a JP-7 surrogate and were validated using avail- able experimental data. These RANS data were then post-processed to obtain, in an a priori fashion, the scalar fields corresponding to an FPV-based modeling approach. In the current work, in addition to the proposed compressible flamelet model, a standard incompressible FPV model was also considered. Several candidate progress variables were investigated for their ability to recover static temperature and major and minor product species. The effects of pressure and temperature on the tabulated progress variable source term were characterized, and model coupling terms embedded in the Reynolds- averaged Navier-Stokes equations were studied. Finally, results for the novel compressible flamelet/progress variable model were presented to demonstrate the improvement attained by modeling the effects of pressure and flamelet boundary conditions on the combustion.

  20. RADIOISOTOPE-DRIVEN DUAL-MODE PROPULSION SYSTEM FOR CUBESAT-SCALE PAYLOADS TO THE OUTER PLANETS

    Energy Technology Data Exchange (ETDEWEB)

    N. D. Jerred; T. M. Howe; S. D. Howe; A. Rajguru

    2014-02-01

    It is apparent the cost of planetary exploration is rising as mission budgets declining. Currently small scientific beds geared to performing limited tasks are being developed and launched into low earth orbit (LEO) in the form of small-scale satellite units, i.e., CubeSats. These micro- and nano-satellites are gaining popularity among the university and science communities due to their relatively low cost and design flexibility. To date these small units have been limited to performing tasks in LEO utilizing solar-based power. If a reasonable propulsion system could be developed, these CubeSat platforms could perform exploration of various extra-terrestrial bodies within the solar system engaging a broader range of researchers. Additionally, being mindful of mass, smaller cheaper launch vehicles (approximately 1,000 kgs to LEO) can be targeted. Thus, in effect, allows for beneficial exploration to be conducted within limited budgets. Researchers at the Center for Space Nuclear Research (CSNR) are proposing a low mass, radioisotope-based, dual-mode propulsion system capable of extending the exploration realm of these CubeSats out of LEO.

  1. MPC-based energy management with adaptive Markov-chain prediction for a dual-mode hybrid electric vehicle

    Institute of Scientific and Technical Information of China (English)

    XIANG; ChangLe; DING; Feng; WANG; WeiDa; HE; Wei; QI; YunLong

    2017-01-01

    The and energy to management strategy battery is state an important part of a hybrid electrical vehicle design.It is used to improve various fuel economy sustain a proper of charge an by controlling control the power components is while satisfying to constraints and driving demands.However,achieving optimal and performance challenging due the nonlinearities of the hybrid powertrain,conflicting vehicle the time varying constraints,the dilemma capable in which controller control complexity and real-time capability are generally objectives.In this paper,a of real-time cascaded complies strategy is proposed for a dual-mode hybrid electric that considers controller based nonlinearities based the system model and with all time-varying with constraints.sampling The strategy consists of a supervisory controller on a non-linear predictive control short(MPC)sampling a long time with future strategy interval and a coordinating on linear model predictive based control with a time interval to deal different load dynamics of the system.The Additionally,a novel data methodology using adaptive Markov chains to predict demand is introduced.predictive future information is used to improve controller cycles performance.conducted.The The proposed is implemented validity on a real test-bed approach and experimental trials using economy unknown is driving are results other demonstrate the of the proposed and show that fuel significantly improved compared with methods.

  2. MPC-based energy management with adaptive Markov-chain prediction for a dual-mode hybrid electric vehicle

    Institute of Scientific and Technical Information of China (English)

    XIANG ChangLe; DING Feng; WANG WeiDa; HE Wei; QI YunLong

    2017-01-01

    The energy management strategy is an important part of a hybrid electrical vehicle design.It is used to improve fuel economy and to sustain a proper battery state of charge by controlling the power components while satisfying various constraints and driving demands.However,achieving an optimal control performance is challenging due to the nonlinearities of the hybrid powertrain,the time varying constraints,and the dilemma in which controller complexity and real-time capability are generally conflicting objectives.In this paper,a real-time capable cascaded control strategy is proposed for a dual-mode hybrid electric vehicle that considers nonlinearities of the system and complies with all time-varying constraints.The strategy consists of a supervisory controller based on a non-linear model predictive control (MPC) with a long sampling time interval and a coordinating controller based on linear model predictive control with a short sampling time interval to deal with different dynamics of the system.Additionally,a novel data based methodology using adaptive Markov chains to predict future load demand is introduced.The predictive future information is used to improve controller performance.The proposed strategy is implemented on a real test-bed and experimental trials using unknown driving cycles are conducted.The results demonstrate the validity of the proposed approach and show that fuel economy is significantly improved compared with other methods.

  3. Multiple player tracking in sports video: a dual-mode two-way bayesian inference approach with progressive observation modeling.

    Science.gov (United States)

    Xing, Junliang; Ai, Haizhou; Liu, Liwei; Lao, Shihong

    2011-06-01

    Multiple object tracking (MOT) is a very challenging task yet of fundamental importance for many practical applications. In this paper, we focus on the problem of tracking multiple players in sports video which is even more difficult due to the abrupt movements of players and their complex interactions. To handle the difficulties in this problem, we present a new MOT algorithm which contributes both in the observation modeling level and in the tracking strategy level. For the observation modeling, we develop a progressive observation modeling process that is able to provide strong tracking observations and greatly facilitate the tracking task. For the tracking strategy, we propose a dual-mode two-way Bayesian inference approach which dynamically switches between an offline general model and an online dedicated model to deal with single isolated object tracking and multiple occluded object tracking integrally by forward filtering and backward smoothing. Extensive experiments on different kinds of sports videos, including football, basketball, as well as hockey, demonstrate the effectiveness and efficiency of the proposed method.

  4. NIR optimized dual mode photoluminescence in Nd doped Y{sub 2}O{sub 3} ceramic phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Sukul, Prasenjit Prasad; Mahata, Manoj Kumar; Kumar, Kaushal, E-mail: kumar.bhu@gmail.com

    2017-05-15

    Authors here report the dual mode photo luminescence emission in neodymium doped yttrium oxide ceramic phosphor upon 808 nm diode laser excitation. Single cubic phase Nd{sup 3+} doped Y{sub 2}O{sub 3} phosphor was synthesized using urea assisted combustion route. Nd{sup 3+} doped Y{sub 2}O{sub 3} ceramic phosphor has given photoluminescence in a wide wavelength range covering near infrared window (850–1100 nm) to the visible region i.e. green (525 nm) and red (680 nm) upon 808 nm diode laser excitation. The two most intense bands on 808 nm excitation were observed at 750 nm and 1064 nm due to the upconversion and downconversion emission processes. The sample was also tested for emission using 980 nm and intense green emission due to the trace presence of Er{sup 3+} in the raw materials was seen in the sample. The excitation power dependent upconversion measurements have shown that transitions {sup 4}F{sub 9/2}→{sup 4}I{sub 9/2} and {sup 4}S{sub 3/2}→{sup 4}I{sub 9/2} are thermally coupled and can be used to estimate the sample temperature using Boltzmann relation.

  5. Effect of curing modes of dual-curing core systems on microtensile bond strength to dentin and formation of an acid-base resistant zone.

    Science.gov (United States)

    Li, Na; Takagaki, Tomohiro; Sadr, Alireza; Waidyasekera, Kanchana; Ikeda, Masaomi; Chen, Jihua; Nikaido, Toru; Tagami, Junji

    2011-12-01

    To evaluate the microtensile bond strength (μTBS) and acid-base resistant zone (ABRZ) of two dualcuring core systems to dentin using four curing modes. Sixty-four caries-free human molars were randomly divided into two groups according to two dual-curing resin core systems: (1) Clearfil DC Core Automix; (2) Estelite Core Quick. For each core system, four different curing modes were applied to the adhesive and core resin: (1) dual-cured and dual-cured (DD); (2) chemically cured and dual-cured (CD); (3) dual-cured and chemically cured (DC); (4) chemically cured and chemically cured (CC). The specimens were sectioned into sticks (n = 20 for each group) for the microtensile bond test. μTBS data were analyzed using two-way ANOVA and the Dunnett T3 test. Failure patterns were examined with scanning electron microscopy (SEM) to determine the proportion of each mode. Dentin sandwiches were produced and subjected to an acid-base challenge. After argon-ion etching, the ultrastructure of ABRZ was observed using SEM. For Clearfil DC Core Automix, the μTBS values in MPa were as follows: DD: 29.1 ± 5.4, CD: 21.6 ± 5.6, DC: 17.9 ± 2.8, CC: 11.5 ± 3.2. For Estelite Core Quick, they were: DD: 48.9 ±5.7, CD: 20.5 ± 4.7, DC: 41.4 ± 8.3, CC: 19.1 ± 6.0. The bond strength was affected by both material and curing mode, and the interaction of the two factors was significant (p < 0.001). Within both systems, there were significant differences among groups, and the DD group showed the highest μTBS (p < 0.05). ABRZ morphology was not affected by curing mode, but it was highly adhesive-material dependent. The curing mode of dual-curing core systems affects bond strength to dentin, but has no significant effect on the formation of ABRZ.

  6. Glioma-targeting micelles for optical/magnetic resonance dual-mode imaging

    Directory of Open Access Journals (Sweden)

    Zhou Q

    2015-03-01

    Full Text Available Qing Zhou,1,* Ketao Mu,2,* Lingyu Jiang,1 Hui Xie,3 Wei Liu,1 Zhengzheng Li,1 Hui Qi,1 Shuyan Liang,1 Huibi Xu,1 Yanhong Zhu,1 Wenzhen Zhu,2 Xiangliang Yang11National Engineering Research Center for Nanomedicine, College of Life Science and Technology, 2Radiology Department, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 3Department of Information Processing, China Patent Information Center, Wuhan, People’s Republic of China*These authors contributed equally to this workAbstract: Surgical resection is the primary mode for glioma treatment, while gross total resection is difficult to achieve, due to the invasiveness of the gliomas. Meanwhile, the tumor-resection region is closely related to survival rate and life quality. Therefore, we developed optical/magnetic resonance imaging (MRI bifunctional targeted micelles for glioma so as to delineate the glioma location before and during operation. The micelles were constructed through encapsulation of hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs with polyethylene glycol-block-polycaprolactone (PEG-b-PCL by using a solvent-evaporation method, and modified with a near-infrared fluorescent probe, Cy5.5, in addition to the glioma-targeting ligand lactoferrin (Lf. Being encapsulated by PEG-b-PCL, the hydrophobic SPIONs dispersed well in phosphate-buffered saline over 4 weeks, and the relaxivity (r2 of micelles was 215.4 mM–1·s–1, with sustained satisfactory fluorescent imaging ability, which might have been due to the interval formed by PEG-b-PCL for avoiding the fluorescence quenching caused by SPIONs. The in vivo results indicated that the nanoparticles with Lf accumulated efficiently in glioma cells and prolonged the duration of hypointensity at the tumor site over 48 hours in the MR image compared to the nontarget group. Corresponding with the MRI results, the margin of the glioma was clearly demarcated in the fluorescence image

  7. A Plasma Based OES-CRDS Dual-mode Portable Spectrometer for Trace Element Detection: Emission and Ringdown Measurements of Mercury

    Science.gov (United States)

    Sahay, Peeyush; Scherrer, Susan; Wang, Chuji

    2012-10-01

    Design and development of a plasma based optical emission spectroscopy-cavity ringdown spectroscopy (OES-CRDS) dual-mode portable spectrometer for in situ monitoring of trace elements is described. A microwave plasma torch (MPT) has been utilized, which serves both as an atomization and excitation source for the two modes, viz. OES and CRDS, of the spectrometer. Operation of both modes of the instrument is demonstrated with initial measurements of elemental mercury (Hg). A detection limit of 44 ng mL-1 for Hg at 253.65 nm was determined with the emission mode of the instrument. Severe radiation trapping of 253.65 nm line hampers the measurement of Hg in higher concentration region (> 50 μg ml-1). Therefore, a different wavelength, 365.01 nm, is suggested to measure Hg in that region. Ringdown measurements of the metastable 6s6p ^3P0 state of Hg in the plasma using a 404.65 nm palm size diode laser was conducted to demonstrate the CRDS mode of the instrument. Along with being portable, dual-mode, and self-calibrated, the instrument is capable of measuring a wide range of concentration ranging from sub ng mL-1 to several μg ml-1 for a number of elements.

  8. Three-phase multilevel inverter configuration for open-winding high power application

    DEFF Research Database (Denmark)

    Sanjeevikumar, Padmanaban; Blaabjerg, Frede; Wheeler, Patrick William

    2015-01-01

    This paper work exploits a new dual open-winding three-phase multilevel inverter configuration suitable for high power medium-voltage applications. Modular structure comprised of standard three-phase voltage source inverter (VSI) along with one additional bi-directional semiconductor device (MOSFET...... for implementation purpose. Proposed dual-inverter configuration generates multilevel outputs with benefit includes reduced THD and dv/dt in comparison to other dual-inverter topologies. Complete model of the multilevel ac drive is developed with simple MSCFM modulation in Matlab/PLECs numerical software...

  9. A dual mode operated boost inverter and its control strategy for ripple current reduction in single-phase uninterruptible power supplies

    DEFF Research Database (Denmark)

    Tang, Y.; Yao, W.; Blaabjerg, Frede

    2015-01-01

    In single-phase uninterruptible power supply (UPS) applications, it is well known that the AC side instantaneous power is not constant by nature. The resulting input current from the DC source side will inevitably contain low frequency ripple components that may largely deteriorate the system...... as active power conversion, while its CM operation is controlled in such a way that the low frequency ripple current on the DC side can be maintained in a minimum level. The proposed ripple current reduction method may not only work with linear loads, but also nonlinear loads, where more sophisticated...

  10. Dual Mode Fluorophore-Doped Nickel Nitrilotriacetic Acid-Modified Silica Nanoparticles Combine Histidine-Tagged Protein Purification with Site-Specific Fluorophore Labeling

    OpenAIRE

    Kim, Sung Hoon; Jeyakumar, M.; Katzenellenbogen, John A.

    2007-01-01

    We present the first example of a fluorophore-doped nickel chelate surface- modified silica nanoparticle that functions in a dual mode, combining histidine-tagged protein purification with site-specific fluorophore labeling. Tetramethylrhodamine (TMR)-doped silica nanoparticles, estimated to contain 700–900 TMRs per ca. 23-nm particle, were surface modified with nitrilotriacetic acid (NTA), producing TMR-SiO2-NTA-Ni+2. Silica-embedded TMR retains very high quantum yield, is resistant to quenc...

  11. A PWM Controller of a Full Bridge Single-Phase Synchronous Inverter for Micro-Grid System

    Science.gov (United States)

    Rahman, Tawfikur; Motakabber, S. M. A.; Ibrahimy, M. I.; Raghib, Aliza ‘Aini Binti Md Ralib@ Md

    2017-12-01

    Nowadays, microgrid system technology is becoming popular for small area power management systems. It is essential to be less harmonic-distortion and high efficiency of the inverter for microgrid applications. Pulse width modulation (PWM) controller is a conventional switching control technique which is suitable to use in the microgrid connected power inverter system. The control method and algorithm of this technique are challenging, and different approaches are required to avoid the complexity for a customized solution of the microgrid application. This paper proposes a comparative analysis of different controller and their operational methods. A PWM controller is used to reduce the ripple voltage noise while a continuous current mode provides a small output ripple which gives steady-state error as zero on fundamental and cutoff frequency. To reduce the ripple current, higher frequency harmonic distortion, switching loss and phase noise, LC low pass filter is used on either side of input and output terminals. The proposed inverter is designed by MATLAB 2016a simulation software. A balanced load resistance (RL = 20.5 Ω) of star configuration and a dual input DC voltage of ± 35V are considered. In this design, the circuit parameters, the fundamental frequency of 50 Hz, the PWM duty cycle of 95%, the cutoff frequency of the switching controller of 33 kHz are considered. The inverter in this paper exhibits THD of 0.44% and overall efficiency approximately of 98%. The proposed inverter is expected to be suitable for microgrid applications.

  12. Dual-wavelength passive and hybrid mode-locking of 3, 4.5 and 10 GHz InAs/InP(100) quantum dot lasers.

    Science.gov (United States)

    Tahvili, M S; Du, L; Heck, M J R; Nötzel, R; Smit, M K; Bente, E A J M

    2012-03-26

    We present an investigation of passive and hybrid mode-locking in Fabry-Pérot type two-section InAs/InP(100) quantum dot lasers that show dual wavelength operation. Over the whole current and voltage range for mode-locking of these lasers, the optical output spectra show two distinct lobes. The two lobes provide a coherent bandwidth and are verified to lead to two synchronized optical pulses. The generated optical pulses are elongated in time due to a chirp which shows opposite signs over the two spectral lobes. Self-induced mode-locking in the single-section laser shows that the dual-wavelength spectra correspond to emission from ground state. In the hybrid mode-locking regime, a map of locking range is presented by measuring the values of timing jitter for several values of power and frequency of the external electrical modulating signal. An overview of the systematic behavior of InAs/InP(100) quantum dot mode-locked lasers is presented as conclusion.

  13. Remote heterodyne millimeter-wave over fiber based OFDM-PON with master-to-slave injected dual-mode colorless FPLD pair.

    Science.gov (United States)

    Chen, Hsiang-Yu; Chi, Yu-Chieh; Lin, Gong-Ru

    2015-08-24

    A remote heterodyne millimeter-wave (MMW) carrier at 47.7 GHz over fiber synthesized with the master-to-slave injected dual-mode colorless FPLD pair is proposed, which enables the future connection between the wired fiber-optic 64-QAM OFDM-PON at 24 Gb/s with the MMW 4-QAM OFDM wireless network at 2 Gb/s. Both the single- and dual-mode master-to-slave injection-locked colorless FPLD pairs are compared to optimize the proposed 64-QAM OFDM-PON. For the unamplified single-mode master, the slave colorless FPLD successfully performs the 64-QAM OFDM data at 24 Gb/s with EVM, SNR and BER of 8.5%, 21.5 dB and 2.9 × 10(-3), respectively. In contrast, the dual-mode master-to-slave injection-locked colorless FPLD pair with amplified and unfiltered master can transmit 64-QAM OFDM data at 18 Gb/s over 25-km SMF to provide EVM, SNR and BER of 8.2%, 21.8 dB and 2.2 × 10(-3), respectively. For the dual-mode master-to-slave injection-locked colorless FPLD pair, even though the modal dispersion occurred during 25-km SMF transmission makes it sacrifice the usable OFDM bandwidth by only 1 GHz, which guarantees the sufficient encoding bitrate for the optically generated MMW carrier to implement the fusion of MMW wireless LAN and DWDM-PON with cost-effective and compact architecture. As a result, the 47.7-GHz MMW carrier remotely beat from the dual-mode master-to-slave injection-locked colorless FPLD pair exhibits an extremely narrow bandwidth of only 0.48 MHz. After frequency down-conversion operation, the 47.7-GHz MMW carrier successfully delivers 4-QAM OFDM data up to 2 Gb/s with EVM, SNR and BER of 33.5%, 9.51 dB and 1.4 × 10(-3), respectively.

  14. Dual-mode T_1 and T_2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application

    International Nuclear Information System (INIS)

    Tegafaw, Tirusew; Xu, Wenlong; Ahmad, Md Wasi; Lee, Gang Ho; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong

    2015-01-01

    A new type of dual-mode T_1 and T_2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd"3"+ ("8S_7_/_2) plays an important role in T_1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy"3"+ ("6H_1_5_/_2) has the potential to be used in T_2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy_2O_3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd"3"+ and Dy"3"+ and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T_1 and T_2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (d_a_v_g = 1.0 nm) showed large r_1 and r_2 values (r_2/r_1 ≈ 6.6) and as a result clear dose-dependent contrast enhancements in R_1 and R_2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T_1 and T_2 MR images. (paper)

  15. Y-source inverter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Town, Graham; Loh, Poh Chiang

    2014-01-01

    This paper introduces a new 3-phase Y-source inverter whose gain is presently not matched by classical impedance-network-based inverters operating at the same duty ratio. The proposed network uses a tightly coupled transformer with three windings. By squeezing the shoot-through range while keeping...... higher boost, the inverter can operate at a higher modulation index, thereby minimizing switching device stress and providing better output power quality. In addition, the inverter has more degrees of freedom for setting the voltage gain and modulation index than other classical impedance-source networks...

  16. A portable optical emission spectroscopy-cavity ringdown spectroscopy dual-mode plasma spectrometer for measurements of environmentally important trace heavy metals: Initial test with elemental Hg

    Science.gov (United States)

    Sahay, Peeyush; Scherrer, Susan T.; Wang, Chuji

    2012-09-01

    A portable optical emission spectroscopy-cavity ringdown spectroscopy (OES-CRDS) dual-mode plasma spectrometer is described. A compact, low-power, atmospheric argon microwave plasma torch (MPT) is utilized as the emission source when the spectrometer is operating in the OES mode. The same MPT serves as the atomization source for ringdown measurements in the CRDS mode. Initial demonstration of the instrument is carried out by observing OES of multiple elements including mercury (Hg) in the OES mode and by measuring absolute concentrations of Hg in the metastable state 6s6p 3P0 in the CRDS mode, in which a palm-size diode laser operating at a single wavelength 405 nm is incorporated in the spectrometer as the light source. In the OES mode, the detection limit for Hg is determined to be 44 parts per 109 (ppb). A strong radiation trapping effect on emission measurements of Hg at 254 nm is observed when the Hg solution concentration is higher than 50 parts per 106 (ppm). The radiation trapping effect suggests that two different transition lines of Hg at 253.65 nm and 365.01 nm be selected for emission measurements in lower (50 ppm), respectively. In the CRDS mode, the detection limit of Hg in the metastable state 6s6p 3P0 is achieved to be 2.24 parts per 1012 (ppt) when the plasma is operating at 150 W with sample gas flow rate of 480 mL min-1; the detection limit corresponds to 50 ppm in Hg sample solution. Advantage of this novel spectrometer has two-fold, it has a large measurement dynamic range, from a few ppt to hundreds ppm and the CRDS mode can serve as calibration for the OES mode as well as high sensitivity measurements. Measurements of seven other elements, As, Cd, Mn, Ni, P, Pb, and Sr, using the OES mode are also carried out with detection limits of 1100, 33, 30, 144, 576, 94, and 2 ppb, respectively. Matrix effect in the presence of other elements on Hg measurements has been found to increase the detection limit to 131 ppb. These elements in lower

  17. Designing a dual-mode broadband solar spectral converter: The example of Bi{sup 3+}, Cr{sup 3+}, Yb{sup 3+}-tridoped perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Li-Tian; Wu, Xuan-Ming; Wang, Ting; Chen, Dong-Ju; Deng, Chao; Meng, Jian-Xin, E-mail: tmjx@jnu.edu.cn; Cao, Li-Wei

    2016-07-15

    A promising dual-mode broadband solar spectral converter CaTiO{sub 3}: Bi{sup 3+}, Cr{sup 3+}, Yb{sup 3+} was successfully developed by solid-stated reaction. The structure, photoluminescence (PL), photoluminescence excitation (PLE) and diffuse reflectance (DR) spectra in the UV–vis–NIR region have been systematically investigated. The results show that the as-prepared samples simultaneously exhibit two distinct spectral converting patterns, nonlinear quantum-cutting (QC) involving Bi{sup 3+}–Ti{sup 4+} metal-to-metal charge transfer state (BT-MMCTs) → Yb{sup 3+}: {sup 2}F{sub 5/2} + Yb{sup 3+}: {sup 2}F{sub 5/2} and linear downshift (DS) involving Cr{sup 3+}: {sup 4}T{sub 2} → Yb{sup 3+}: {sup 2}F{sub 5/2}. It deduces that the nonlinear QC is based on a cooperative energy transfer (CET) process while the linear DS belongs to a dipole–dipole mechanism. With the present converter, broadband UV–vis (300–700 nm) photons, which are not fully utilized by the existing c-Si solar cells, can be efficiently harvested and converted into ∼1000 nm NIR photons via the dual-mode mechanism. Moreover, not only the PLE spectrum of CaTiO{sub 3}: Bi{sup 3+}, Cr{sup 3+}, Yb{sup 3+} matched well with that of the solar radiation, but also its NIR emission peak position fell well over the spectral response of the commercial crystalline Si (c-Si) solar cells. This as-prepared dual-mode solar spectral converter with multiple advantages can simultaneously realize high quantum yield and broadband conversion, which offers a new and effective way to boost the conversion efficiency of c-Si solar cells. We believe this novel design of dual-mode solar spectral converters can inspire a direction for the synthesis of more advanced UV–vis–NIR phosphors that can be used in Si solar cells. - Highlights: • A dual-mode broadband solar spectral converter is designed and developed. • The energy transfer mechanism relies on quantum-cutting as well as downshift. • The PLE

  18. Analysis of Dual- and Full-Circular Polarimetric SAR Modes for Rice Phenology Monitoring: An Experimental Investigation through Ground-Based Measurements

    Directory of Open Access Journals (Sweden)

    Yuta Izumi

    2017-04-01

    Full Text Available Circularly polarized synthetic aperture radar (CP-SAR is known to be insensitive to polarization mismatch losses caused by the Faraday rotation effect and antenna misalignment. Additionally, the dual-circular polarimetric (DCP mode has proven to have more polarimetric information than that of the corresponding mode of linear polarization, i.e., the dual-linear polarimetric (DLP mode. Owing to these benefits, this paper investigates the feasibility of CP-SAR for rice monitoring. A ground-based CP-radar system was exploited, and C-band anechoic chamber data of a self-cultivated Japanese rice paddy were acquired from germination to ripening stages. Temporal variations of polarimetric observables derived from full-circular polarimetric (FCP and DCP as well as synthetically generated DLP data are analyzed and assessed with regard to their effectiveness in phenology retrieval. Among different observations, the H / α ¯ plane and triangle plots obtained by three scattering components (surface, double-bounce, and volume scattering for both the FCP and DCP modes are confirmed to have reasonable capability in discriminating the relevant intervals of rice growth.

  19. Power inverter implementing phase skipping control

    Science.gov (United States)

    Somani, Utsav; Amirahmadi, Ahmadreza; Jourdan, Charles; Batarseh, Issa

    2016-10-18

    A power inverter includes a DC/AC inverter having first, second and third phase circuitry coupled to receive power from a power source. A controller is coupled to a driver for each of the first, second and third phase circuitry (control input drivers). The controller includes an associated memory storing a phase skipping control algorithm, wherein the controller is coupled to receive updating information including a power level generated by the power source. The drivers are coupled to control inputs of the first, second and third phase circuitry, where the drivers are configured for receiving phase skipping control signals from the controller and outputting mode selection signals configured to dynamically select an operating mode for the DC/AC inverter from a Normal Control operation and a Phase Skipping Control operation which have different power injection patterns through the first, second and third phase circuitry depending upon the power level.

  20. Next Generation Inverter

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zilai [General Motors LLC, Detroit, MI (United States); Gough, Charles [General Motors LLC, Detroit, MI (United States)

    2016-04-22

    The goal of this Cooperative Agreement was the development of a Next Generation Inverter for General Motors’ electrified vehicles, including battery electric vehicles, range extended electric vehicles, plug-in hybrid electric vehicles and hybrid electric vehicles. The inverter is a critical electronics component that converts battery power (DC) to and from the electric power for the motor (AC).

  1. Modular inverter system

    Science.gov (United States)

    Ma, Mingyao; Hu, Haibing; Kutkut, Nasser; Batarseh, Issa; Shen, John; , Bkayrat, Raed

    2017-08-01

    A system connected to an AC power grid having an AC phase signal includes an inverter module including a first inverter coupled to a DC voltage, actuated based on the AC phase signal. The first inverter provides a first voltage signal having predetermined harmonic components. A second inverter includes second switch elements coupled to the DC voltage and actuated by a second set of control signals phase delayed with respect to the first control signals. A transformer module has first and second primary windings coupled to the first and second inverters. The transformer module further includes a secondary winding coupled to first primary winding, the second primary winding, and the AC power grid. The secondary winding is configured to provide a secondary output voltage to the AC power grid by combining the first voltage signal and the second voltage signal such that the predetermined harmonic components are substantially cancelled.

  2. Research on a six-phase permanent magnet synchronous motor system at dual-redundant and fault tolerant modes in aviation application

    Directory of Open Access Journals (Sweden)

    Xiaolin KUANG

    2017-08-01

    Full Text Available With the development of more/all electrical aircraft technology, an electro-mechanical actuator (EMA is more and more used in an aircraft actuation system. The motor system, as the crucial part of an EMA, usually adopts the redundancy technology or fault tolerance technology to improve the reliability. To compare the performances of these two motor systems, a 10-pole/12-slot six-phase permanent magnet synchronous motor (PMSM is designed with the concentrated single-layer winding, which is able to operate at dual-redundant and fault tolerant modes. Furthermore, the position servo performances of the six-phase PMSM at dual-redundant and fault tolerant modes are analyzed, including the normal and fault conditions. In addition, a variable structure proportional-integral-derivative (PID control strategy is proposed to solve the performance degradation problem caused by phase current saturation. Simulation and experimental results show that the fault tolerant PMSM has a better position servo performance than the dual-redundant PMSM, and the variable structure PID control strategy is able to improve the performance due to phase current saturation.

  3. Effect of curing mode on the hardness of dual-cured composite resin core build-up materials

    Directory of Open Access Journals (Sweden)

    César Augusto Galvão Arrais

    2010-06-01

    Full Text Available This study evaluated the Knoop Hardness (KHN values of two dual-cured composite resin core build-up materials and one resin cement exposed to different curing conditions. Two dual-cured core build-up composite resins (LuxaCore®-Dual, DMG; and FluoroCore®2, Dentsply Caulk, and one dual-cured resin cement (Rely X ARC, 3M ESPE were used in the present study. The composite materials were placed into a cylindrical matrix (2 mm in height and 3 mm in diameter, and the specimens thus produced were either light-activated for 40 s (Optilux 501, Demetron Kerr or were allowed to self-cure for 10 min in the dark (n = 5. All specimens were then stored in humidity at 37°C for 24 h in the dark and were subjected to KHN analysis. The results were submitted to 2-way ANOVA and Tukey's post-hoc test at a pre-set alpha of 5%. All the light-activated groups exhibited higher KHN values than the self-cured ones (p = 0.00001, regardless of product. Among the self-cured groups, both composite resin core build-up materials showed higher KHN values than the dual-cured resin cement (p = 0.00001. LuxaCore®-Dual exhibited higher KHN values than FluoroCore®2 (p = 0.00001 when they were allowed to self-cure, while no significant differences in KHN values were observed among the light-activated products. The results suggest that dual-cured composite resin core build-up materials may be more reliable than dual-cured resin cements when curing light is not available.

  4. Temporal resolution measurement of 128-slice dual source and 320-row area detector computed tomography scanners in helical acquisition mode using the impulse method.

    Science.gov (United States)

    Hara, Takanori; Urikura, Atsushi; Ichikawa, Katsuhiro; Hoshino, Takashi; Nishimaru, Eiji; Niwa, Shinji

    2016-04-01

    To analyse the temporal resolution (TR) of modern computed tomography (CT) scanners using the impulse method, and assess the actual maximum TR at respective helical acquisition modes. To assess the actual TR of helical acquisition modes of a 128-slice dual source CT (DSCT) scanner and a 320-row area detector CT (ADCT) scanner, we assessed the TRs of various acquisition combinations of a pitch factor (P) and gantry rotation time (R). The TR of the helical acquisition modes for the 128-slice DSCT scanner continuously improved with a shorter gantry rotation time and greater pitch factor. However, for the 320-row ADCT scanner, the TR with a pitch factor of pitch factor of >1.0, it was approximately one half of the gantry rotation time. The maximum TR values of single- and dual-source helical acquisition modes for the 128-slice DSCT scanner were 0.138 (R/P=0.285/1.5) and 0.074s (R/P=0.285/3.2), and the maximum TR values of the 64×0.5- and 160×0.5-mm detector configurations of the helical acquisition modes for the 320-row ADCT scanner were 0.120 (R/P=0.275/1.375) and 0.195s (R/P=0.3/0.6), respectively. Because the TR of a CT scanner is not accurately depicted in the specifications of the individual scanner, appropriate acquisition conditions should be determined based on the actual TR measurement. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  5. Mathematical model for the preliminary analysis of dual-mode space nuclear fission solid core power and propulsion systems, NUROC3A. AMS report No. 1239a

    Energy Technology Data Exchange (ETDEWEB)

    Grey, J.; Chow, S.

    1976-06-30

    The three-volume report describes a dual-mode nuclear space power and propulsion system concept that employs an advanced solid-core nuclear fission reactor coupled via heat pipes to one of several electric power conversion systems. Such a concept could be particularly useful for missions which require both relatively high acceleration (e.g., for planetocentric maneuvers) and high performance at low acceleration (e.g., on heliocentric trajectories or for trajectory shaping). The first volume develops the mathematical model of the system.

  6. Voltage resonant inverter as a power source

    OpenAIRE

    Lupenko, Anatoliy; Stakhiv, Petro

    2014-01-01

    The operation mode of a voltage resonant inverter as a power source with variable load is analyzed. In order to reduce load power variations, an approach to development of the inverter’s load power response based on providing similar positive and negative power deviations from its nominal value has been proposed. The design procedure for resonant inverter with open loop structure as a power source has been elaborated. For a high pressure sodium lamp as a load, the power deviation of about 4% ...

  7. Resting State Default Mode Network Connectivity, Dual Task Performance, Gait Speed, and Postural Sway in Older Adults with Mild Cognitive Impairment.

    Science.gov (United States)

    Crockett, Rachel A; Hsu, Chun Liang; Best, John R; Liu-Ambrose, Teresa

    2017-01-01

    Aging is associated with an increased risk of falling. In particular, older adults with mild cognitive impairment (MCI) are more vulnerable to falling compared with their healthy counterparts. Major contributors to this increased falls risk include a decline in dual task performance, gait speed, and postural sway. Recent evidence highlights the potential influence of the default mode network (DMN), the frontoparietal network (FPN), and the supplementary motor area (SMA) on dual task performance, gait speed, and postural sway. The DMN is active during rest and deactivates during task-oriented processes, to maintain attention and stay on task. The FPN and SMA are involved in top-down attentional control, motor planning, and motor execution. The DMN shows less deactivation during task in older adults with MCI. This lack of deactivation is theorized to increase competition for resources between the DMN and task-related brain regions (e.g., the FPN and SMA), increasing distraction from the task and reducing task performance. However, no study has yet investigated the relationship between the between-network connectivity of the DMN with these regions and dual task walking, gait speed or postural sway. We hypothesized that greater functional connectivity both within the DMN and between DMN-FPN and DMN-SMA, will be associated with poorer performance during dual task walking, slower gait speed, and greater postural sway in older adults with MCI. Forty older adults with MCI were measured on a dual task-walking paradigm, gait speed over a 4-m walk, and postural sway using a sway-meter. Greater within-DMN connectivity was significantly correlated with poorer dual task performance. Furthermore, greater inter-network connectivity between the DMN and SMA was significantly correlated with slower gait speed and greater postural sway on the eyes open floor sway task. Thus, greater resting state DMN functional connectivity may be an underlying neural mechanism for reduced dual task

  8. Reliable inverter systems

    Science.gov (United States)

    Nagano, S.

    1979-01-01

    Base driver with common-load-current feedback protects paralleled inverter systems from open or short circuits. Circuit eliminates total system oscillation that can occur in conventional inverters because of open circuit in primary transformer winding. Common feedback signal produced by functioning modules forces operating frequency of failed module to coincide with clock drive so module resumes normal operating frequency in spite of open circuit.

  9. A MEMS and agile optics-based dual-mode variable optical power splitter with no moving parts

    Science.gov (United States)

    Khwaja, Tariq S.; Suleman, Hamid; Reza, Syed Azer

    2017-06-01

    In this paper, we present a novel design of an optical power splitter. Owing to the inherent variable power split ratios that the proposed design delivers, it is ideal for use in communications, sensing and signal processing applications where variable power splitting is often quintessential. The proposed power splitter module is dual mode as it combines the use of a Micro-Electro-Mechanical Systems (MEMS) based Digital Micro-mirror Device (DMD) and an Electronically Controlled Tunable Lens (ECTL) to split the power of an input optical signal between two output ports - the designated port and the surplus port. The use of a reflective Digital Spatial Light Modulator (DSLM) such as the DMD provides a motion-free digital control of the split ratio between the two output ports. Although the digital step between two possible successive split ratios can be fairly minimal with the use of a high resolution DMD but it is a challenge to correctly ascertain the exact image pattern on the DMD to obtain any desired specific split ratio. To counter this challenge, we propose the synchronized use of a circular pattern on the DMD, which serves as a circular clear aperture with a tunable radius, and an ECTL. The radius of the circular pattern on the DMD provides a digital control of the split ratio between the two ports whereas the ECTL, depending on its controller, can provide either an analog or a digital control by altering the beam radius which is incident at the DMD circular pattern. The radius of the circular pattern on the DMD can be minimally changed by one micro-pixel thickness. Setting the radius of the circular pattern on the DMD to an appropriate value provides the closest "ball-park" split ratio whereas further tuning the ECTL aids in slightly altering from this digitally set value to obtain the exact desired split ratio in-between any two digitally-set successive split ratios that correspond to any clear aperture radius of the DMD pattern and its incremental minimal

  10. Cross-mode bioelectrical impedance analysis in a standing position for estimating fat-free mass validated against dual-energy x-ray absorptiometry.

    Science.gov (United States)

    Huang, Ai-Chun; Chen, Yu-Yawn; Chuang, Chih-Lin; Chiang, Li-Ming; Lu, Hsueh-Kuan; Lin, Hung-Chi; Chen, Kuen-Tsann; Hsiao, An-Chi; Hsieh, Kuen-Chang

    2015-11-01

    Bioelectrical impedance analysis (BIA) is commonly used to assess body composition. Cross-mode (left hand to right foot, Z(CR)) BIA presumably uses the longest current path in the human body, which may generate better results when estimating fat-free mass (FFM). We compared the cross-mode with the hand-to-foot mode (right hand to right foot, Z(HF)) using dual-energy x-ray absorptiometry (DXA) as the reference. We hypothesized that when comparing anthropometric parameters using stepwise regression analysis, the impedance value from the cross-mode analysis would have better prediction accuracy than that from the hand-to-foot mode analysis. We studied 264 men and 232 women (mean ages, 32.19 ± 14.95 and 34.51 ± 14.96 years, respectively; mean body mass indexes, 24.54 ± 3.74 and 23.44 ± 4.61 kg/m2, respectively). The DXA-measured FFMs in men and women were 58.85 ± 8.15 and 40.48 ± 5.64 kg, respectively. Multiple stepwise linear regression analyses were performed to construct sex-specific FFM equations. The correlations of FFM measured by DXA vs. FFM from hand-to-foot mode and estimated FFM by cross-mode were 0.85 and 0.86 in women, with standard errors of estimate of 2.96 and 2.92 kg, respectively. In men, they were 0.91 and 0.91, with standard errors of the estimates of 3.34 and 3.48 kg, respectively. Bland-Altman plots showed limits of agreement of -6.78 to 6.78 kg for FFM from hand-to-foot mode and -7.06 to 7.06 kg for estimated FFM by cross-mode for men, and -5.91 to 5.91 and -5.84 to 5.84 kg, respectively, for women. Paired t tests showed no significant differences between the 2 modes (P > .05). Hence, cross-mode BIA appears to represent a reasonable and practical application for assessing FFM in Chinese populations. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Comparison of prospective electrocardiography-gating high-pitch mode and without electrocardiography-synchronization high-pitch mode acquisition for the image quality and radiation doses of the aortic using dual-source CT

    International Nuclear Information System (INIS)

    Li Jian; Huan Yi; Zhao Hongliang; Wang Ying; Liu Ying; Wei Mengqi; Shi Mingguo; Zheng Minwen

    2013-01-01

    Objective: To evaluate the application of prospective ECG-gating Flash spiral scan mode dual-source CT in aortography, and compare it's image quality and radiation dose with without ECG-synchronization high-pitch spiral scanning mode. Methods: Fifty consecutive patients (Group A) with suspected aortic dissection or after operations for the aortic dissection were scanned with prospective ECG-gated high-pitch scan and another 50 consecutive patients (Group B) were analyzed by non-ECG-gated high-pitch scan. Image quality of the aortic was assessed by two independent readers. Image noise was measured, radiation dose estimates were calculated. The imaging quality of the aortic and the radiation dose were compared with Mann-whitney U and t test. Results: The average image quality score [(1.18 ± 0.40) in group A and (1.23 ± 0.31) in group B] showed no significant difference between group A and group B (U = 1.20, P = 0.23). The mean radiation dose of group A was lower than that of group B [(1.49 ± 0.38) mSv in group A, (2.79 ± 0.54) mSv in group B, t = 13.677, P < 0.05]. Conclusion: Prospective ECG-gated dual source CT Flash spiral scanning with low radiation dose and good image quality in the aortic dissection with high value of clinical application. (authors)

  12. Large-area, uniform and low-cost dual-mode plasmonic naked-eye colorimetry and SERS sensor with handheld Raman spectrometer.

    Science.gov (United States)

    Xu, Zhida; Jiang, Jing; Wang, Xinhao; Han, Kevin; Ameen, Abid; Khan, Ibrahim; Chang, Te-Wei; Liu, Gang Logan

    2016-03-21

    We demonstrated a highly-sensitive, wafer-scale, highly-uniform plasmonic nano-mushroom substrate based on plastic for naked-eye plasmonic colorimetry and surface-enhanced Raman spectroscopy (SERS). We gave it the name FlexBrite. The dual-mode functionality of FlexBrite allows for label-free qualitative analysis by SERS with an enhancement factor (EF) of 10(8) and label-free quantitative analysis by naked-eye colorimetry with a sensitivity of 611 nm RIU(-1). The SERS EF of FlexBrite in the wet state was found to be 4.81 × 10(8), 7 times stronger than in the dry state, making FlexBrite suitable for aqueous environments such as microfluid systems. The label-free detection of biotin-streptavidin interaction by both SERS and colorimetry was demonstrated with FlexBrite. The detection of trace amounts of the narcotic drug methamphetamine in drinking water by SERS was implemented with a handheld Raman spectrometer and FlexBrite. This plastic-based dual-mode nano-mushroom substrate has the potential to be used as a sensing platform for easy and fast analysis in chemical and biological assays.

  13. Dual-mode fluorophore-doped nickel nitrilotriacetic acid-modified silica nanoparticles combine histidine-tagged protein purification with site-specific fluorophore labeling.

    Science.gov (United States)

    Kim, Sung Hoon; Jeyakumar, M; Katzenellenbogen, John A

    2007-10-31

    We present the first example of a fluorophore-doped nickel chelate surface-modified silica nanoparticle that functions in a dual mode, combining histidine-tagged protein purification with site-specific fluorophore labeling. Tetramethylrhodamine (TMR)-doped silica nanoparticles, estimated to contain 700-900 TMRs per ca. 23 nm particle, were surface modified with nitrilotriacetic acid (NTA), producing TMR-SiO2-NTA-Ni2+. Silica-embedded TMR retains very high quantum yield, is resistant to quenching by buffer components, and is modestly quenched and only to a certain depth (ca. 2 nm) by surface-attached Ni2+. When exposed to a bacterial lysate containing estrogen receptor alpha ligand binding domain (ERalpha) as a minor component, these beads showed very high specificity binding, enabling protein purification in one step. The capacity and specificity of these beads for binding a his-tagged protein were characterized by electrophoresis, radiometric counting, and MALDI-TOF MS. ERalpha, bound to TMR-SiO2-NTA-Ni++ beads in a site-specific manner, exhibited good activity for ligand binding and for ligand-induced binding to coactivators in solution FRET experiments and protein microarray fluorometric and FRET assays. This dual-mode type TMR-SiO2-NTA-Ni2+ system represents a powerful combination of one-step histidine-tagged protein purification and site-specific labeling with multiple fluorophore species.

  14. Microgeneration of electricity with producer gas in dual fuel mode operation Microgeração de eletricidade com gás de gaseificação num motor gerador dual

    Directory of Open Access Journals (Sweden)

    Marcelo J. Silva

    2011-10-01

    Full Text Available Among the alternatives to meet the increasing of world demand for energy, the use of biomass as energy source is one of the most promising as it contributes to reducing emissions of carbon dioxide in the atmosphere. Gasification is a technological process of biomass energy production of a gaseous biofuel. The fuel gas has a low calorific value that can be used in Diesel engine in dual mode for power generation in isolated communities. This study aimed to evaluate the reduction in the consumption of oil Diesel an engine generator, using gas from gasification of wood. The engine generator brand used was a BRANCO, with direct injection power of 7.36 kW (10 HP coupled to an electric generator 5.5 kW. Diesel oil mixed with intake air was injected, as the oil was injected via an injector of the engine (dual mode. The fuel gas was produced in a downdraft gasifier. The engine generator was put on load system from 0.5 kW to 3.5 kW through a set of electrical resistances. Diesel oil consumption was measured with a precision scale. It was concluded that the engine converted to dual mode when using the gas for the gasification of wood decreased Diesel consumption by up to 57%.Dentre as alternativas à crescente demanda energética mundial, o uso da biomassa como fonte de energia é uma das formas mais promissoras, pois contribui para a redução das emissões de dióxido de carbono na atmosfera. A gaseificação é uma tecnologia de transformação energética da biomassa num biocombustível gasoso. O gás de gaseificação é um combustível de baixo poder calorífico que pode ser utilizado em motor ciclo Diesel no modo dual para geração de energia elétrica em comunidades isoladas. Este trabalho teve por objetivo avaliar a redução no consumo de Diesel num motor gerador, com a utilização de gás da gaseificação da madeira. O motor avaliado foi da marca BRANCO, com injeção direta e potência de 7,36 kW (10 cv acoplado a um gerador elétrico de 5

  15. High-temperature superconducting coplanar-waveguide quarter-wavelength resonator with odd- and even-mode resonant frequencies for dual-band bandpass filter

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Kei; Takagi, Yuta; Narahashi, Shoichi [Research Laboratories, NTT DOCOMO, INC., 3-6 Hikari-no-oka Yokosuka, Kanagawa 239-8536 Japan (Japan); Nojima, Toshio, E-mail: satokei@nttdocomo.co.j [Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0814 Japan (Japan)

    2010-06-01

    This paper presents a high-temperature superconducting coplanar-waveguide quarter-wavelength resonator that has two different resonant modes for use in a dual-band bandpass filter (DBPF). An RF filter with multiple passbands such as the DBPF is a basic element that is expected to achieve broadband transmission by using separated frequency bands aggregately and simultaneously in future mobile communication systems. The proposed resonator has a folded center conductor and two open stubs that are aligned close to it. The odd- and even-mode resonant frequencies are configured using the space between the folded center conductor and the open stubs. It is easy to configure the odd- and even-mode coupling coefficients independently because the two resonant modes have different current density distributions. Consequently, a DBPF with two different bandwidths can be easily designed. This paper presents three design examples for a four-pole Chebyshev DBPF with different combinations of fractional bandwidths in order to investigate the validity of the proposed resonator. This paper also presents measured results of the DBPF based on the design examples from the standpoint of experimental investigation. The designed and measured frequency responses confirm that the proposed resonator is effective in achieving DBPFs not only with two of the same bandwidths but also with two different bandwidths.

  16. A dual-mode nanosensor based on carbon quantum dots and gold nanoparticles for discriminative detection of glutathione in human plasma.

    Science.gov (United States)

    Shi, Yupeng; Pan, Yi; Zhang, Heng; Zhang, Zhaomin; Li, Mei-Jin; Yi, Changqing; Yang, Mengsu

    2014-06-15

    Glutathione (GSH) plays key roles in biological systems and serves many cellular functions. Since biothiols all incorporate thiol, carboxylic and amino groups, discriminative detection of GSH over cysteine (Cys) and homocysteine (Hcy) is still challenging. We herein report a dual-mode nanosensor with both colorimetric and fluorometric readout based on carbon quantum dots and gold nanoparticles for discriminative detection of GSH over Cys/Hcy. The proposed sensing system consists of AuNPs and fluorescent carbon quantum dots (CQDs), where CQDs function as fluorometric reporter, and AuNPs serve a dual function as colorimetric reporter and fluorescence quencher. The mechanism of the nanosensor is based on two distance-dependent phenomenons, color change of AuNPs and FRET. Through controlling the surface properties of as-prepared nanoparticles, the addition of CQDs into AuNPs colloid solution might induce the aggregation of AuNPs and CQDs, leading to AuNPs color changing from red to blue and CQDs fluorescence quench. However, the presence of GSH can protect AuNPs from being aggregated and enlarge the inter-particle distance, which subsequently produces color change and fluorescent signal recovery. The nanosensor described in this report reflects on its simplicity and flexibility, where no further surface functionalization is required for the as-prepared nanoparticles, leading to less laborious and more cost-effective synthesis. The proposed dual-mode nanosensor demonstrated highly selectivity toward GSH, and allows the detection of GSH as low as 50 nM. More importantly, the nanosensor could not only function in aqueous solution for GSH detection with high sensitivity but also exhibit sensitive responses toward GSH in complicated biological environments, demonstrating its potential in bioanalysis and biodection, which might be significant in disease diagnosis in the future. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. The dual exo/endo-type mode and the effect of ionic strength on the mode of catalysis of chitinase 60 (CHI60) from Serratia sp. TU09 and its mutants.

    Science.gov (United States)

    Kuttiyawong, K; Nakapong, S; Pichyangkura, R

    2008-11-03

    Mutations of the tryptophan residues in the tryptophan-track of the N-terminal domain (W33F/Y and W69F/Y) and in the catalytic domain (W245F/Y) of Serratia sp. TU09 Chitinase 60 (CHI60) were constructed, as single and double point substitutions to either phenylalanine or tyrosine. The enzyme-substrate interaction and mode of catalysis, exo/endo-type, of wild type CHI60 and mutant enzymes on soluble (partially N-acetylated chitin), amorphous (colloidal chitin), and crystalline (β-chitin) substrates were studied. All CHI60 mutants exhibited a reduced substrate binding activity on colloidal chitin. CHI60 possesses a dual mode of catalysis with both exo- and endo-type activities allowing the enzyme to work efficiently on various substrate types. CHI60 preferentially uses the endo-type mode on soluble and amorphous substrates and the exo-type mode on crystalline substrate. However, the prevalent mode of hydrolysis mediated by CHI60 is regulated by ionic strength. Slightly elevated ionic strength, 0.1-0.2M NaCl, which promotes enzyme-substrate interactions, enhances CHI60 hydrolytic activity on amorphous substrate and, interestingly, on partially N-acetylated chitin. High ionic strength, 0.5-2.0M NaCl, prevents the enzyme from dissociating from amorphous substrate, occupying the enzyme in an enzyme-substrate non-productive complex. However, on crystalline substrates, the activity of CHI60 was only inhibited approximately 50% at high ionic strength, suggesting that the enzyme hydrolyzes crystalline substrates with an exo-type mode processively while remaining tightly bound to the substrate. Moreover, substitution of Trp-33 to either phenylalanine or tyrosine reduced the activity of the enzyme at high ionic strength, suggesting an important role of Trp-33 on enzyme processivity.

  18. Rayleigh instability of the inverted one-cell amphibian embryo

    International Nuclear Information System (INIS)

    Nouri, Comron; Gordon, Richard; Luppes, Roel; Veldman, Arthur E P; Tuszynski, Jack A

    2008-01-01

    The one-cell amphibian embryo is modeled as a rigid spherical shell containing equal volumes of two immiscible fluids with different densities and viscosities and a surface tension between them. The fluids represent denser yolk in the bottom hemisphere and clearer cytoplasm and the germinal vesicle in the top hemisphere. The unstable equilibrium configuration of the inverted system (the heavier fluid on top) depends on the value of the contact angle. The theoretically calculated normal modes of perturbation and the instability of each mode are in agreement with the results from ComFlo computational fluid dynamic simulations of the same system. The two dominant types of modes of perturbation give rise to axisymmetric and asymmetric sloshing of the cytoplasm of the inverted embryos, respectively. This work quantifies our hypothesis that the axisymmetric mode corresponds to failure of development, and the asymmetric sloshing mode corresponds to development proceeding normally, but with reversed pigmentation, for inverted embryos

  19. Resonant snubber inverter

    Science.gov (United States)

    Lai, Jih-Sheng; Young, Sr., Robert W.; Chen, Daoshen; Scudiere, Matthew B.; Ott, Jr., George W.; White, Clifford P.; McKeever, John W.

    1997-01-01

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  20. Component mode synthesis methods applied to 3D heterogeneous core calculations, using the mixed dual finite element solver MINOS

    Energy Technology Data Exchange (ETDEWEB)

    Guerin, P.; Baudron, A. M.; Lautard, J. J. [Commissariat a l' Energie Atomique, DEN/DANS/DM2S/SERMA/LENR, CEA Saclay, 91191 Gif sur Yvette (France)

    2006-07-01

    This paper describes a new technique for determining the pin power in heterogeneous core calculations. It is based on a domain decomposition with overlapping sub-domains and a component mode synthesis technique for the global flux determination. Local basis functions are used to span a discrete space that allows fundamental global mode approximation through a Galerkin technique. Two approaches are given to obtain these local basis functions: in the first one (Component Mode Synthesis method), the first few spatial eigenfunctions are computed on each sub-domain, using periodic boundary conditions. In the second one (Factorized Component Mode Synthesis method), only the fundamental mode is computed, and we use a factorization principle for the flux in order to replace the higher order Eigenmodes. These different local spatial functions are extended to the global domain by defining them as zero outside the sub-domain. These methods are well-fitted for heterogeneous core calculations because the spatial interface modes are taken into account in the domain decomposition. Although these methods could be applied to higher order angular approximations - particularly easily to a SPN approximation - the numerical results we provide are obtained using a diffusion model. We show the methods' accuracy for reactor cores loaded with UOX and MOX assemblies, for which standard reconstruction techniques are known to perform poorly. Furthermore, we show that our methods are highly and easily parallelizable. (authors)

  1. Component mode synthesis methods applied to 3D heterogeneous core calculations, using the mixed dual finite element solver MINOS

    International Nuclear Information System (INIS)

    Guerin, P.; Baudron, A. M.; Lautard, J. J.

    2006-01-01

    This paper describes a new technique for determining the pin power in heterogeneous core calculations. It is based on a domain decomposition with overlapping sub-domains and a component mode synthesis technique for the global flux determination. Local basis functions are used to span a discrete space that allows fundamental global mode approximation through a Galerkin technique. Two approaches are given to obtain these local basis functions: in the first one (Component Mode Synthesis method), the first few spatial eigenfunctions are computed on each sub-domain, using periodic boundary conditions. In the second one (Factorized Component Mode Synthesis method), only the fundamental mode is computed, and we use a factorization principle for the flux in order to replace the higher order Eigenmodes. These different local spatial functions are extended to the global domain by defining them as zero outside the sub-domain. These methods are well-fitted for heterogeneous core calculations because the spatial interface modes are taken into account in the domain decomposition. Although these methods could be applied to higher order angular approximations - particularly easily to a SPN approximation - the numerical results we provide are obtained using a diffusion model. We show the methods' accuracy for reactor cores loaded with UOX and MOX assemblies, for which standard reconstruction techniques are known to perform poorly. Furthermore, we show that our methods are highly and easily parallelizable. (authors)

  2. SEEPAGE/INVERT INTERACTIONS

    International Nuclear Information System (INIS)

    P.S. Domski

    2000-01-01

    As directed by a written development plan (CRWMS M andO 1999a), a conceptual model for water entering the drift and reacting with the invert materials is to be developed. The purpose of this conceptual model is to assist Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction, and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near-Field Environment (NFE), Revision 2 (NRC 1999). This AMR also seeks to: (1) Develop a logical conceptual model for physical/chemical interactions between seepage and the invert materials; (2) screen potential processes and reactions that may occur between seepage and invert to evaluate the potential consequences of the interactions; and (3) outline how seepage/invert processes may be quantified. This document provides the conceptual framework for screening out insignificant processes and for identifying and evaluating those seepage/invert interactions that have the potential to be important to subsequent PAO analyses including the Engineered Barrier System (EBS) physical and chemical model abstraction effort. This model has been developed to serve as a basis for the in-drift geochemical analyses performed by PAO. Additionally, the concepts discussed within this report may also apply to certain near and far-field geochemical processes and may have conceptual application within the unsaturated zone (UZ) and saturated zone (SZ) transport modeling efforts. The seepage/invert interactions will not directly affect any principal factors

  3. Grid-connected to/from off-grid transference for micro-grid inverters

    OpenAIRE

    Heredero Peris, Daniel; Chillón Antón, Cristian; Pages Gimenez, Marc; Gross, Gabriel Igor; Montesinos Miracle, Daniel

    2013-01-01

    This paper compares two methods for controlling the on-line transference from connected to stand-alone mode and vice versa in converters for micro-grids. The first proposes a method where the converter changes from CSI (Current Source Inverter) in grid-connected mode to VSI (Voltage Source Inverter) in off-grid. In the second method, the inverter always works as a non-ideal voltage source, acting as VSI, using AC droop control strategy.

  4. Multipurpose, dual-mode imaging in the 3-5 μm range (MWIR) for artwork diagnostics: A systematic approach

    Science.gov (United States)

    Daffara, Claudia; Parisotto, Simone; Ambrosini, Dario

    2018-05-01

    We present a multi-purpose, dual-mode imaging method in the Mid-Wavelength Infrared (MWIR) range (from 3 μm to 5 μm) for a more efficient nondestructive analysis of artworks. Using a setup based on a MWIR thermal camera and multiple radiation sources, two radiometric image datasets are acquired in different acquisition modalities, the image in quasi-reflectance mode (TQR) and the thermal sequence in emission mode. Here, the advantages are: the complementarity of the information; the use of the quasi-reflectance map for calculating the emissivity map; the use of TQR map for a referentiation to the visible of the thermographic images. The concept of the method is presented, the practical feasibility is demonstrated through a custom imaging setup, the potentiality for the nondestructive analysis is shown on a notable application to cultural heritage. The method has been used as experimental tool in support of the restoration of the mural painting "Monocromo" by Leonardo da Vinci. Feedback from the operators and a comparison with some conventional diagnostic techniques is also given to underline the novelty and potentiality of the method.

  5. A dual-mode secure UHF RFID tag with a crypto engine in 0.13-μm CMOS

    Science.gov (United States)

    Tao, Yang; Linghao, Zhu; Xi, Tan; Junyu, Wang; Lirong, Zheng; Hao, Min

    2016-07-01

    An ultra-high-frequency (UHF) radio frequency identification (RFID) secure tag chip with a non-crypto mode and a crypto mode is presented. During the supply chain management, the tag works in the non-crypto mode in which the on-chip crypto engine is not enabled and the tag chip has a sensitivity of -12.8 dBm for long range communication. At the point of sales (POS), the tag will be switched to the crypto mode in order to protect the privacy of customers. In the crypto mode, an advanced encryption standard (AES) crypto engine is enabled and the sensitivity of the tag chip is switched to +2 dBm for short range communication, which is a method of physical protection. The tag chip is implemented and verified in a standard 0.13-μm CMOS process. Project supported by the National Science & Technology Pillar Program of China (No. 2015BAK36B01).

  6. Challenging Ubiquitous Inverted Files

    NARCIS (Netherlands)

    de Vries, A.P.

    2000-01-01

    Stand-alone ranking systems based on highly optimized inverted file structures are generally considered ‘the’ solution for building search engines. Observing various developments in software and hardware, we argue however that IR research faces a complex engineering problem in the quest for more

  7. Energy-Saving Inverter

    Science.gov (United States)

    Rippel, W. E.; Edwards, D. B.

    1984-01-01

    Commutation by field-effect transistor allows more efficient operation. High voltage field-effect transistor (FET) controls silicon controlled rectifiers (SCR's). Circuit requires only one capacitor and one inductor in commutation circuit: simpler, more efficient, and more economical than conventional inverters. Adaptable to dc-to-dc converters.

  8. Argonne inverted sputter source

    International Nuclear Information System (INIS)

    Yntema, J.L.; Billquist, P.J.

    1983-01-01

    The emittance of the inverted sputter source with immersion lenses was measured to be about 5π mm mrad MeV/sup 1/2/ at the 75% level over a wide range of beam intensities. The use of the source in experiments with radioactive sputter targets and hydrogen loaded targets is described. Self contamination of the source is discussed

  9. Prospectively Electrocardiogram-Gated High-Pitch Spiral Acquisition Mode Dual-Source CT Coronary Angiography in Patients with High Heart Rates: Comparison with Retrospective Electrocardiogram-Gated Spiral Acquisition Mode

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kai; Ma, Rui; Wang, Li Jun [Dept. of Radiology, Baotou Central Hospital, Baotou (China); Li, Li Gang; Chen, Jiu Hong [CT BM Clinic Marketing, Siemens Healthcare, Beijing (China)

    2012-11-15

    To assess the image quality and effective radiation dose of prospectively electrocardiogram (ECG)-gated high-pitch spiral acquisition mode (flash mode) of dual-source CT (DSCT) coronary angiography (CTCA) in patients with high heart rates (HRs) as compared with retrospectively ECG-gated spiral acquisition mode. Two hundred and sixty-eight consecutive patients (132 female, mean age: 55 {+-} 11 years) with mean HR > 65 beats per minute (bpm) were prospectively included in this study. The patients were divided into two groups. Collection was performed in group A CTCA using flash mode setting at 20-30% of the R-R interval, and retrospectively ECG-gated spiral acquisition mode in group B. The image noise, contrast-to-noise ratio (CNR), image quality scores, effective radiation dose and influencing factors on image quality between the two groups were assessed. There were no significant differences in image quality scores and proportions of non-diagnostic coronary artery segments between two groups (image quality scores: 1.064 {+-} 0.306 [group A] vs. 1.084 {+-} 0.327 [group B], p = 0.063; proportion of non-diagnostic coronary artery segments: segment-based analysis 1.52% (group A) vs. 1.74% (group B), p = 0.345; patient-based analysis 7.5% (group A) vs. 6.7% (group B), p = 0.812). The estimated radiation dose was 1.0 {+-} 0.16 mSv in group A and 7.1 {+-} 1.05 mSv in group B (p = 0.001). In conclusion, in patients with HRs > 65 bpm without cardiac arrhythmia, the prospectively high-pitch spiral-acquisition mode with image-acquired timing set at 20-30% of the R-R interval provides a similar image quality and low rate of non-diagnostic coronary segments to the retrospectively ECG-gated low-pitch spiral acquisition mode, with significant reduction of radiation exposure.

  10. Prospectively Electrocardiogram-Gated High-Pitch Spiral Acquisition Mode Dual-Source CT Coronary Angiography in Patients with High Heart Rates: Comparison with Retrospective Electrocardiogram-Gated Spiral Acquisition Mode

    International Nuclear Information System (INIS)

    Sun, Kai; Ma, Rui; Wang, Li Jun; Li, Li Gang; Chen, Jiu Hong

    2012-01-01

    To assess the image quality and effective radiation dose of prospectively electrocardiogram (ECG)-gated high-pitch spiral acquisition mode (flash mode) of dual-source CT (DSCT) coronary angiography (CTCA) in patients with high heart rates (HRs) as compared with retrospectively ECG-gated spiral acquisition mode. Two hundred and sixty-eight consecutive patients (132 female, mean age: 55 ± 11 years) with mean HR > 65 beats per minute (bpm) were prospectively included in this study. The patients were divided into two groups. Collection was performed in group A CTCA using flash mode setting at 20-30% of the R-R interval, and retrospectively ECG-gated spiral acquisition mode in group B. The image noise, contrast-to-noise ratio (CNR), image quality scores, effective radiation dose and influencing factors on image quality between the two groups were assessed. There were no significant differences in image quality scores and proportions of non-diagnostic coronary artery segments between two groups (image quality scores: 1.064 ± 0.306 [group A] vs. 1.084 ± 0.327 [group B], p = 0.063; proportion of non-diagnostic coronary artery segments: segment-based analysis 1.52% (group A) vs. 1.74% (group B), p = 0.345; patient-based analysis 7.5% (group A) vs. 6.7% (group B), p = 0.812). The estimated radiation dose was 1.0 ± 0.16 mSv in group A and 7.1 ± 1.05 mSv in group B (p = 0.001). In conclusion, in patients with HRs > 65 bpm without cardiac arrhythmia, the prospectively high-pitch spiral-acquisition mode with image-acquired timing set at 20-30% of the R-R interval provides a similar image quality and low rate of non-diagnostic coronary segments to the retrospectively ECG-gated low-pitch spiral acquisition mode, with significant reduction of radiation exposure.

  11. Quality Factor and Radiation Efficiency of Dual-Mode Self-Resonant Spherical Antennas With Lossy Magnetodielectric Cores

    DEFF Research Database (Denmark)

    Hansen, Troels Vejle; Kim, Oleksiy S.; Breinbjerg, Olav

    2014-01-01

    For spherical antennas consisting of a solid magnetodielectric lossy core with an impressed surface current density exciting a superposition of the ${\\rm TE}_{mn}$ and ${\\rm TM}_{mn}$ spherical modes, we analytically determine the radiation quality factor $Q$ and radiation efficiency $e$ . Also, we...

  12. Component mode synthesis methods for 3-D heterogeneous core calculations applied to the mixed-dual finite element solver MINOS

    International Nuclear Information System (INIS)

    Guerin, P.; Baudron, A.M.; Lautard, J.J.; Van Criekingen, S.

    2007-01-01

    This paper describes a new technique for determining the pin power in heterogeneous three-dimensional calculations. It is based on a domain decomposition with overlapping sub-domains and a component mode synthesis (CMS) technique for the global flux determination. Local basis functions are used to span a discrete space that allows fundamental global mode approximation through a Galerkin technique. Two approaches are given to obtain these local basis functions. In the first one (the CMS method), the first few spatial eigenfunctions are computed on each sub-domain, using periodic boundary conditions. In the second one (factorized CMS method), only the fundamental mode is computed, and we use a factorization principle for the flux in order to replace the higher-order Eigenmodes. These different local spatial functions are extended to the global domain by defining them as zero outside the sub-domain. These methods are well fitted for heterogeneous core calculations because the spatial interface modes are taken into account in the domain decomposition. Although these methods could be applied to higher-order angular approximations-particularly easily to an SPN approximation-the numerical results we provide are obtained using a diffusion model. We show the methods' accuracy for reactor cores loaded with uranium dioxide and mixed oxide assemblies, for which standard reconstruction techniques are known to perform poorly. Furthermore, we show that our methods are highly and easily parallelizable. (authors)

  13. Current Harmonics from Single-Phase Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    Environmental conditions and operational modes may significantly impact the distortion level of the injected current from single-phase grid-connected inverter systems, such as photovoltaic (PV) inverters, which may operate in cloudy days with a maximum power point tracking, in a non-unity power...... factor, or in the low voltage ride through mode with reactive current injection. In this paper, the mechanism of the harmonic current injection from grid-connected single-phase inverter systems is thus explored, and the analysis is conducted on single-phase PV systems. In particular, the analysis...... is focused on the impacts of the power factor and the feed-in grid current level on the quality of the feed-in grid current from single-phase inverters. As a consequence, an internal model principle based high performance current control solution is tailor-made and developed for single-phase grid-connected...

  14. Stochastic p -Bits for Invertible Logic

    Science.gov (United States)

    Camsari, Kerem Yunus; Faria, Rafatul; Sutton, Brian M.; Datta, Supriyo

    2017-07-01

    Conventional semiconductor-based logic and nanomagnet-based memory devices are built out of stable, deterministic units such as standard metal-oxide semiconductor transistors, or nanomagnets with energy barriers in excess of ≈40 - 60 kT . In this paper, we show that unstable, stochastic units, which we call "p -bits," can be interconnected to create robust correlations that implement precise Boolean functions with impressive accuracy, comparable to standard digital circuits. At the same time, they are invertible, a unique property that is absent in standard digital circuits. When operated in the direct mode, the input is clamped, and the network provides the correct output. In the inverted mode, the output is clamped, and the network fluctuates among all possible inputs that are consistent with that output. First, we present a detailed implementation of an invertible gate to bring out the key role of a single three-terminal transistorlike building block to enable the construction of correlated p -bit networks. The results for this specific, CMOS-assisted nanomagnet-based hardware implementation agree well with those from a universal model for p -bits, showing that p -bits need not be magnet based: any three-terminal tunable random bit generator should be suitable. We present a general algorithm for designing a Boltzmann machine (BM) with a symmetric connection matrix [J ] (Ji j=Jj i) that implements a given truth table with p -bits. The [J ] matrices are relatively sparse with a few unique weights for convenient hardware implementation. We then show how BM full adders can be interconnected in a partially directed manner (Ji j≠Jj i) to implement large logic operations such as 32-bit binary addition. Hundreds of stochastic p -bits get precisely correlated such that the correct answer out of 233 (≈8 ×1 09) possibilities can be extracted by looking at the statistical mode or majority vote of a number of time samples. With perfect directivity (Jj i=0 ) a small

  15. Quasi-Y-source inverter

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    This paper introduces a new inverter topology called a “quasi-Y-source inverter”. The proposed inverter inherits all the advantages of the original Y-source inverter. In addition, the new topology draws continuous current from the source which is required for many renewable sources. It also has dc......-current-blocking capacitors, which avoids saturation in the transformer core. Simulations and experimental results have proved the validity of the proposed inverter....

  16. Inverter communications using output signal

    Science.gov (United States)

    Chapman, Patrick L.

    2017-02-07

    Technologies for communicating information from an inverter configured for the conversion of direct current (DC) power generated from an alternative source to alternating current (AC) power are disclosed. The technologies include determining information to be transmitted from the inverter over a power line cable connected to the inverter and controlling the operation of an output converter of the inverter as a function of the information to be transmitted to cause the output converter to generate an output waveform having the information modulated thereon.

  17. Liquid-phase sample preparation method for real-time monitoring of airborne asbestos fibers by dual-mode high-throughput microscopy.

    Science.gov (United States)

    Cho, Myoung-Ock; Kim, Jung Kyung; Han, Hwataik; Lee, Jeonghoon

    2013-01-01

    Asbestos that had been used widely as a construction material is a first-level carcinogen recognized by the World Health Organization. It can be accumulated in body by inhalation causing virulent respiratory diseases including lung cancer. In our previous study, we developed a high-throughput microscopy (HTM) system that can minimize human intervention accompanied by the conventional phase contrast microscopy (PCM) through automated counting of fibrous materials and thus significantly reduce analysis time and labor. Also, we attempted selective detection of chrysotile using DksA protein extracted from Escherichia coli through a recombinant protein production technique, and developed a dual-mode HTM (DM-HTM) by upgrading the HTM device. We demonstrated that fluorescently-labeled chrysotile asbestos fibers can be identified and enumerated automatically among other types of asbestos fibers or non-asbestos particles in a high-throughput manner through a newly modified HTM system for both reflection and fluorescence imaging. However there is a limitation to apply DM-HTM to airborne sample with current air collecting method due to the difficulty of applying the protein to dried asbestos sample. Here, we developed a technique for preparing liquid-phase asbestos sample using an impinger normally used to collect odor molecules in the air. It would be possible to improve the feasibility of the dual-mode HTM by integrating a sample preparation unit for making collected asbestos sample dispersed in a solution. The new technique developed for highly sensitive and automated asbestos detection can be a potential alternative to the conventional manual counting method, and it may be applied on site as a fast and reliable environmental monitoring tool.

  18. Hyaluronic acid-modified manganese-chelated dendrimer-entrapped gold nanoparticles for the targeted CT/MR dual-mode imaging of hepatocellular carcinoma

    Science.gov (United States)

    Wang, Ruizhi; Luo, Yu; Yang, Shuohui; Lin, Jiang; Gao, Dongmei; Zhao, Yan; Liu, Jinguo; Shi, Xiangyang; Wang, Xiaolin

    2016-09-01

    Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver. The early and effective diagnosis has always been desired. Herein, we present the preparation and characterization of hyaluronic acid (HA)-modified, multifunctional nanoparticles (NPs) targeting CD44 receptor-expressing cancer cells for computed tomography (CT)/magnetic resonance (MR) dual-mode imaging. We first modified amine-terminated generation 5 poly(amidoamine) dendrimers (G5.NH2) with an Mn chelator, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), fluorescein isothiocyanate (FI), and HA. Then, gold nanoparticles (AuNPs) were entrapped within the above raw product, denoted as G5.NH2-FI-DOTA-HA. The designed multifunctional NPs were formed after further Mn chelation and purification and were denoted as {(Au0)100G5.NH2-FI-DOTA(Mn)-HA}. These NPs were characterized via several different techniques. We found that the {(Au0)100G5.NH2-FI-DOTA(Mn)-HA} NPs exhibited good water dispersibility, stability under different conditions, and cytocompatibility within a given concentration range. Because both AuNPs and Mn were present in the product, {(Au0)100G5.NH2-FI-DOTA(Mn)-HA} displayed a high X-ray attenuation intensity and favorable r1 relaxivity, which are advantageous properties for targeted CT/MR dual-mode imaging. This approach was used to image HCC cells in vitro and orthotopically transplanted HCC tumors in a unique in vivo model through the CD44 receptor-mediated endocytosis pathway. This work introduces a novel strategy for preparing multifunctional NPs via dendrimer nanotechnology.

  19. A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering.

    Science.gov (United States)

    Shen, Chong; Li, Jie; Zhang, Xiaoming; Shi, Yunbo; Tang, Jun; Cao, Huiliang; Liu, Jun

    2016-05-31

    The different noise components in a dual-mass micro-electromechanical system (MEMS) gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN), electronic-thermal noise (ETN), flicker noise (FN) and Coriolis signal in-phase noise (IPN). The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD) and time-frequency peak filtering (TFPF). There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs) by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods.

  20. A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering

    Directory of Open Access Journals (Sweden)

    Chong Shen

    2016-05-01

    Full Text Available The different noise components in a dual-mass micro-electromechanical system (MEMS gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN, electronic-thermal noise (ETN, flicker noise (FN and Coriolis signal in-phase noise (IPN. The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD and time-frequency peak filtering (TFPF. There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods.

  1. A single phase photovoltaic inverter control for grid connected system

    Indian Academy of Sciences (India)

    This paper presents a control scheme for single phase grid connected photovoltaic (PV) system operating under both grid connected and isolated grid mode. The control techniques include voltage and current control of grid-tie PV inverter. During grid connected mode, grid controls the amplitude and frequency of the PV ...

  2. Inverting the Linear Algebra Classroom

    Science.gov (United States)

    Talbert, Robert

    2014-01-01

    The inverted classroom is a course design model in which students' initial contact with new information takes place outside of class meetings, and students spend class time on high-level sense-making activities. The inverted classroom model is so called because it inverts or "flips" the usual classroom design where typically class…

  3. Milliwatt dc/dc Inverter

    Science.gov (United States)

    Mclyman, C. W.

    1983-01-01

    Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.

  4. Dual mode emission and harmonic generation in ZnO-CaO-Al{sub 2}O{sub 3}: Er{sup 3+} nano-composite

    Energy Technology Data Exchange (ETDEWEB)

    Verma, R.K. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Kumar, K. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Nano-technology Application Centre, University of Allahabad, Allahabad (India); Rai, S.B., E-mail: sbrai49@yahoo.co.i [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India)

    2011-05-15

    Er{sup 3+} doped ZnO-CaO-Al{sub 2}O{sub 3} nano-composite phosphor has been synthesized through combustion method and its emission and harmonic generation properties have been studied. The X-ray diffraction and thermal analysis techniques have been used to prove the dual phase (ZnO and CaO-Al{sub 2}O{sub 3}) nature of the phosphor. The phosphor has shown up-conversion emission on near-infra-red (976 nm) excitation and down-conversion emission on 355 nm excitation in presence of Er{sup 3+} and thus behaves as a dual mode phosphor. On excitation with 976 nm diode laser, material shows color tunability (calcination of composite material at different temperatures). Formation of ZnO nanocrystals on heat treatment of as-synthesized sample has shown its characteristic emission at 388 nm and also the energy transfer from ZnO to Er{sup 3+} ions. The low temperature emission measurements have been carried out and the results have been discussed. Phosphor has shown strong second harmonic generation (SHG) at 532 nm on 1064 nm and at 266 nm on 532 nm excitation. - Research highlights: {yields} We have synthesized Er{sup 3+} doped composite material by combustion method. The two phases of composites are ZnO and CaO-Al{sub 2}O{sub 3}. {yields} The phosphor has shown up-conversion emission on near-infra-red (976 nm) excitation and down-conversion emission on 355 nm excitation in presence of Er{sup 3+} and thus behaves as a dual mode phosphor. This material also shows colour tenability on excitation of 976 nm diode laser at different temperature calcinations (i.e., As-synthesized to calcinated at 1473 K). {yields} Low temperature effects on Er{sup 3+} as well as ZnO emission have been carried out. We observed that at low temperature the efficiency of Er{sup 3+} increases while in the case of ZnO its intensity increases and also 12 nm shifting observed. {yields} Composite material has shown strong second harmonic generation (SHG) at 532 nm on 1064 nm and at 266 nm on 532 nm

  5. Analysis and Design of Solar Photo voltaic Grid Connected Inverter

    Directory of Open Access Journals (Sweden)

    Muddasani Satyanarayana

    2015-08-01

    Full Text Available This paper presents common mode voltage analysis of single phase grid connected photovoltaic inverter. Many researchers proposed different grid tie inverters for applications like domestic powering, street lighting, water pumping, cooling and heating applications, however traditional grid tie PV inverter uses either a line frequency or a high frequency transformer between the inverter and grid but losses will increase in the network leading to reduced efficiency of the system. In order to increase the efficiency, with reduced size and cost of the system, the effective solution is to remove the isolation transformer. But common mode (CM ground leakage current due to parasitic capacitance between the PV panels and the ground making the system unreliable. The common mode current reduces the efficiency of power conversion stage, affects the quality of grid current, deteriorate the electric magnetic compatibility and give rise to the safety threats. In order to eliminate the common mode leakage current in Transformerless PV systm two control algorithms of multi-carrier pwm are implemented and compared for performance analysis.The shoot-through issue that is encountered by traditional voltage source inverter is analyzed for enhanced system reliability. These control algorithms are compared for common mode voltage and THD comparisons. The proposed system is designed using MATLAB/SIMULINK software for analysis.

  6. Solar Power Station Output Inverter Control Design

    Directory of Open Access Journals (Sweden)

    J. Bauer

    2011-04-01

    Full Text Available The photovoltaic applications spreads in these days fast, therefore they also undergo great development. Because the amount of the energy obtained from the panel depends on the surrounding conditions, as intensity of the sun exposure or the temperature of the solar array, the converter must be connected to the panel output. The Solar system equipped with inverter can supply small loads like notebooks, mobile chargers etc. in the places where the supplying network is not present. Or the system can be used as a generator and it shall deliver energy to the supply network. Each type of the application has different requirements on the converter and its control algorithm. But for all of them the one thing is common – the maximal efficiency. The paper focuses on design and simulation of the low power inverter that acts as output part of the whole converter. In the paper the design of the control algorithm of the inverter for both types of inverter application – for islanding mode and for operation on the supply grid – is discussed. Attention is also paid to the design of the output filter that should reduce negative side effects of the converter on the supply network.

  7. Proposed Novel Multiphase-Multilevel Inverter Configuration for Open-End Winding Loads

    DEFF Research Database (Denmark)

    Padamanaban, Sanjeevi Kumar; Wheeler, Patrick; Blaabjerg, Frede

    2016-01-01

    This paper presents a new multiphase-multilevel inverter configuration for open-winding loads and suitable for medium power (low-voltage/high-current) applications such as `More Electric Aircraft'. Modular structure comprised of standard dual three-phase voltage source inverter (VSI) along with one...... is developed in this work and overcomes the complexity of standard space vector modulations, easy for real implementation purposes in digital processors. Proposed six-phase multilevel inverter configuration generates multilevel outputs with benefit in comprises with standard multilevel inverter topologies...

  8. Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: A phantom study

    International Nuclear Information System (INIS)

    Hwang, Sung Ho; Oh, Yu Whan; Ham, Soo Youn; Kang, Eun Young; Lee, Ki Yeol

    2015-01-01

    To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 +/- 0.9%, and 1.7 +/- 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 +/- 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 +/- 5.3%), with an IVV of 13.1 +/- 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size. The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.

  9. Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Sung Ho; Oh, Yu Whan; Ham, Soo Youn [Dept. of Radiology, Korea University Anam Hospital, Seoul (Korea, Republic of); Kang, Eun Young [Dept. of Radiology, Korea University Guro Hospital, Seoul (Korea, Republic of); Lee, Ki Yeol [Dept. of Radiology, Korea University Ansan Hospital, Ansan (Korea, Republic of)

    2015-06-15

    To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 +/- 0.9%, and 1.7 +/- 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 +/- 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 +/- 5.3%), with an IVV of 13.1 +/- 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size. The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.

  10. Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: a phantom study.

    Science.gov (United States)

    Hwang, Sung Ho; Oh, Yu-Whan; Ham, Soo-Youn; Kang, Eun-Young; Lee, Ki Yeol

    2015-01-01

    To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 ± 0.9%, and 1.7 ± 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 ± 7.4%) was significantly greater (p volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.

  11. Inverter ratio failure detector

    Science.gov (United States)

    Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (Inventor)

    1974-01-01

    A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

  12. Computer code and users' guide for the preliminary analysis of dual-mode space nuclear fission solid core power and propulsion systems, NUROC3A. AMS report No. 1239b

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, R.A.; Smith, W.W.

    1976-06-30

    The three-volume report describes a dual-mode nuclear space power and propulsion system concept that employs an advanced solid-core nuclear fission reactor coupled via heat pipes to one of several electric power conversion systems. The second volume describes the computer code and users' guide for the preliminary analysis of the system.

  13. Prediction of the binding mode and resistance profile for a dual-target pyrrolyl diketo acid scaffold against HIV-1 integrase and reverse-transcriptase-associated ribonuclease H.

    Science.gov (United States)

    Yang, Fengyuan; Zheng, Guoxun; Fu, Tingting; Li, Xiaofeng; Tu, Gao; Li, Ying Hong; Yao, Xiaojun; Xue, Weiwei; Zhu, Feng

    2018-06-27

    The rapid emergence of drug-resistant variants is one of the most common causes of highly active antiretroviral therapeutic (HAART) failure in patients infected with HIV-1. Compared with the existing HAART, the recently developed pyrrolyl diketo acid scaffold targeting both HIV-1 integrase (IN) and reverse transcriptase-associated ribonuclease H (RNase H) is an efficient approach to counteract the failure of anti-HIV treatment due to drug resistance. However, the binding mode and potential resistance profile of these inhibitors with important mechanistic principles remain poorly understood. To address this issue, an integrated computational method was employed to investigate the binding mode of inhibitor JMC6F with HIV-1 IN and RNase H. By using per-residue binding free energy decomposition analysis, the following residues: Asp64, Thr66, Leu68, Asp116, Tyr143, Gln148 and Glu152 in IN, Asp443, Glu478, Trp536, Lys541 and Asp549 in RNase H were identified as key residues for JMC6F binding. And then computational alanine scanning was carried to further verify the key residues. Moreover, the resistance profile of the currently known major mutations in HIV-1 IN and 2 mutations in RNase H against JMC6F was predicted by in silico mutagenesis studies. The results demonstrated that only three mutations in HIV-1 IN (Y143C, Q148R and N155H) and two mutations in HIV-1 RNase H (Y501R and Y501W) resulted in a reduction of JMC6F potency, thus indicating their potential role in providing resistance to JMC6F. These data provided important insights into the binding mode and resistance profile of the inhibitors with a pyrrolyl diketo acid scaffold in HIV-1 IN and RNase H, which would be helpful for the development of more effective dual HIV-1 IN and RNase H inhibitors.

  14. Response mode, compatibility, and dual-processes in the evaluation of simple gambles: An eye-tracking investigation

    Directory of Open Access Journals (Sweden)

    Paul Slovic

    2012-07-01

    Full Text Available We employed simple gambles to investigate information processing in relation to the compatibility effect. Subjects should be more likely to engage in a deliberative thinking strategy when completing a pricing task rather than a rating task. We used eye-tracking methodology to measure information acquisition and processing in order to test the above hypothesis as well as to show that losses and alternatives with uncertain outcomes are more likely than gains and alternatives with sure outcomes to be processed through a deliberative thinking process. Results showed that pupil dilations, fixation duration and number of fixations increased when subjects evaluated the gambles with a pricing task. Additionally, the number of fixations increased as the gamble outcome became increasingly negative and when the outcome was uncertain (vs. sure. Fixations were also predictive of subjects' final evaluations of the gambles. We discuss our results in light of the cognitive processes underlying different response modes in economic preferences.

  15. Dual-mode photoacoustic and ultrasound system for real-time in-vivo ovarian cancer imaging

    Science.gov (United States)

    Mostafa, Atahar; Nandy, Sreyankar; Amidi, Eghbal; Zhu, Quing

    2018-02-01

    More than 80% of the ovarian cancers are diagnosed at late stages and the survival rate is less than 50%. Currently, there is no effective screening technique available and transvaginal US can only tell if the ovaries are enlarged or not. We have developed a new real-time co-registered US and photoacoustic system for in vivo imaging and characterization of ovaries. US is used to localize ovaries and photoacoustic imaging provides functional information about ovarian tissue angiogenesis and oxygenation saturation. The system consists of a tunable laser and a commercial US system from Alpinion Inc. The Alpinion system is cable of providing channel data for both US pulse-echo and photoacoustic imaging and can be programmed as a computer terminal for display US and photoacoustic images side by side or in coregistered mode. A transvaginal ultrasound probe of 6-MHz center frequency and bandwidth of 3-10 MHz is coupled with four optical fibers surrounded the US probe to deliver the light to tissue. The light from optical fibers is homogenized to ensure the power delivered to the tissue surface is below the FDA required limit. Physicians can easily navigate the probe and use US to look for ovaries and then turn on photoacoustic mode to provide real-time tumor vasculature and So2 saturation maps. With the optimized system, we have successfully imaged first group of 7 patients of malignant, abnormal and benign ovaries. The results have shown that both photoacoustic signal strength and spatial distribution are different between malignant and abnormal and benign ovaries.

  16. A Novel Approach to Synthesise a Dual-Mode Luminescent Composite Pigment for Uncloneable High-Security Codes to Combat Counterfeiting.

    Science.gov (United States)

    Kanika; Kumar, Pawan; Singh, Satbir; Gupta, Bipin Kumar

    2017-12-01

    A strategy is demonstrated to protect valuable items, such as currency, pharmaceuticals, important documents, etc. against counterfeiting, by marking them with luminescent security codes. These luminescent security codes were printed by employing luminescent ink formulated from a cost effective dual-mode luminescent composite pigment of Gd 1.7 Yb 0.2 Er 0.1 O 3 and Zn 0.98 Mn 0.02 S phosphors using commercially available PVC Gold medium. In the composite, Gd 1.7 Yb 0.2 Er 0.1 O 3 and Zn 0.98 Mn 0.02 S account for upconversion and downconversion processes, respectively. The synthesis procedure of the composite involves the admixing of Gd 1.7 Yb 0.2 Er 0.1 O 3 nanorods and Zn 0.98 Mn 0.02 S phosphor, synthesised by hydrothermal and facile solid-state reaction methods, respectively. The structural, morphological, microstructural, and photoluminescent features of Gd 1.7 Yb 0.2 Er 0.1 O 3 nanorods, Zn 0.98 Mn 0.02 S phosphor and composite were characterised by using XRD, SEM, TEM, and photoluminescence (PL) techniques, respectively. The distribution of PL intensity of the printed pattern was examined by using confocal PL mapping microscopy. The obtained results reveal that security codes printed using ink formulated from this bi-luminescent composite pigment provide dual-stage security against counterfeiting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Analysis of a combustion, performance and emission characteristics of a CNG-B20 fuelled diesel engine under dual fuel mode

    Directory of Open Access Journals (Sweden)

    Pankaj S. Shelke

    2016-09-01

    Full Text Available The Carbon dioxide (CO2 is one of the primary greenhouse gases emitted by various human activities. CO2 is naturally present in the atmosphere as part of carbon cycle. Human activities are altering the carbon cycle by adding or removing CO2 to the atmosphere. The main human activity that emits the CO2 is combustion of fossil fuels for energy and transportation. Compression ignition (CI engines emit high amount of CO2 emission as it is the end product of complete combustion of hydro carbon fuels. Moreover, they emit higher NOx (nitrogen oxides and PM (particulate matter emissions and have higher fuel consumption. In the present study, experimental investigations were carried out on a CI engine under dual fuel mode with biodiesel as a pilot fuel and compressed natural gas (CNG as a main fuel. The effects of 10 % and 20 % CNG energy shares on performance and emission characteristics of the engine at rated (100% loads were studied. Experimental results indicate the beneficial of CNG addition on improvement in the engine efficiency, and reduction in NOx and CO2 emissions. The NOx and CO2 emissions decreased by 14.24 % and 30 % respectively at the rated load with biodiesel + CNG (20 % energy share as compared to base diesel. No knocking combustion was observed during the tests which confirm the smooth operation. The dual fuel operation with combination of CNG-biodiesel is an effective method to reduce NOx and CO2 emissions with an additional benefit of lower specific energy consumption.

  18. Yb{sup 3+},Er{sup 3+},Eu{sup 3+}-codoped YVO{sub 4} material for bioimaging with dual mode excitation

    Energy Technology Data Exchange (ETDEWEB)

    Thao, Chu Thi Bich [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Huy, Bui The [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Da Nang (Viet Nam); Sharipov, Mirkomil [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Kim, Jin-Ik. [Department of Biochemistry and Health Science, Changwon National University, Changwon 641-773 (Korea, Republic of); Dao, Van-Duong [Department of Chemical Engineering & Applied Chemistry, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Moon, Ja-Young [Department of Biochemistry and Health Science, Changwon National University, Changwon 641-773 (Korea, Republic of); Lee, Yong-Ill, E-mail: yilee@changwon.ac.kr [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of)

    2017-06-01

    We propose an efficient bioimaging strategy using Yb{sup 3+},Er{sup 3+},Eu{sup 3+}-triplet doped YVO{sub 4} nanoparticles which were synthesized with polymer as a template. The obtained particles possess nanoscale, uniform, and flexible excitation. The effect of Eu{sup 3+} ions on the luminescence properties of YVO{sub 4}:Yb{sup 3+},Er{sup 3+},Eu{sup 3+} was investigated. The upconversion mechanism of the prepared material was also discussed. The structure and optical properties of the prepared material were characterized by using X-ray diffraction (XRD), Fourier-transform IR spectroscopy (FTIR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM) upconversion and photoluminescence spectra. The Commission International de I′Eclairage (CIE) chromaticity coordinates was investigated to confirm the performance of color luminescent emission. The prepared YVO{sub 4}:Yb{sup 3+},Er{sup 3+},Eu{sup 3+} nanoparticles could be easily dispersed in water by surface modification with cysteine (Cys) and glutathione (GSH). The aqueous dispersion of the modified YVO{sub 4}:Yb{sup 3+},Er{sup 3+},Eu{sup 3+} exhibits bright upconversion and downconversion luminescence and has been applied for bioimaging of HeLa cells. Our developed material with dual excitation offers a promising advance in bioimaging. - Highlights: • Prepared particles possess nanoscale size, uniform, and larger scale. • The material exhibits strong emission under dual mode excitations. • The surface material has been applied for bioimaging of HeLa cell. • Low cytotoxicity, no auto-fluorescence.

  19. Contrast Dose and Radiation Dose Reduction in Abdominal Enhanced Computerized Tomography Scans with Single-phase Dual-energy Spectral Computerized Tomography Mode for Children with Solid Tumors.

    Science.gov (United States)

    Yu, Tong; Gao, Jun; Liu, Zhi-Min; Zhang, Qi-Feng; Liu, Yong; Jiang, Ling; Peng, Yun

    2017-04-05

    Contrast dose and radiation dose reduction in computerized tomography (CT) scan for adult has been explored successfully, but there have been few studies on the application of low-concentration contrast in pediatric abdominal CT examinations. This was a feasibility study on the use of dual-energy spectral imaging and adaptive statistical iterative reconstruction (ASiR) for the reduction of radiation dose and iodine contrast dose in pediatric abdominal CT patients with solid tumors. Forty-five patients with solid tumors who had initial CT (Group B) and follow-up CT (Group A) after chemotherapy were enrolled. The initial diagnostic CT scan (Group B) was performed using the standard two-phase enhanced CT with 320 mgI/ml concentration contrast, and the follow-up scan (Group A) was performed using a single-phase enhanced CT at 45 s after the beginning of the 270 mgI/ml contrast injection using spectral mode. Forty percent ASiR was used for the images in Group B and monochromatic images with energy levels ≥60 keV in Group A. In addition, filtered back-projection (FBP) reconstruction was used for monochromatic images hounsfield unit (HU). The abdominal organs of Groups A and B had similar degrees of absolute and relative enhancement (t = 0.36 and -1.716 for liver, -0.153 and -1.546 for pancreas, and 2.427 and 0.866 for renal cortex, all P> 0.05). Signal-to-noise ratio of the abdominal organs was significantly lower in Group A than in Group B (t = -8.11 for liver, -7.83 for pancreas, and -5.38 for renal cortex, all P 3, indicating clinically acceptable image quality. Single-phase, dual-energy spectral CT used for children with solid abdominal tumors can reduce contrast dose and radiation dose and can also maintain clinically acceptable image quality.

  20. Research on a Compound Control Strategy of Three-Phase Inverter for Unbalanced Loads

    Directory of Open Access Journals (Sweden)

    Yue Gaili

    2017-01-01

    Full Text Available To solve the problem of unbalanced output voltage of inverter under three-phase unbalanced load. In this paper, the main circuit topology using three-phase three-wire inverter topology. Established the mathematical model in several different coordinate system of the three-phase inverter. A compound control method is proposed by combining voltage current dual loop control method and repetitive control method, The control method is realized in three - phase 400 Hz inverter, and can meet the demand of unbalanced load to inverter, the reliability of the inverter circuit is improved. At the end of this paper, Matlab simulation analysis and experimental results are given, it is proved that the composite control method designed in this paper has a strong ability of unbalanced load.

  1. Advances in PV Inverters

    DEFF Research Database (Denmark)

    Anthon, Alexander

    and preferably low complexity leads to new research demands. This is especially true in the field of low cost residential PV inverters where efficiencies are used as major selling arguments. Traditional converter topologies equipped with conventional Silicon based semiconductors to date reach their limitations......, a replacement of only two switching devices per phase leg can greatly reduce the semiconductor losses. The Hybrid-NPC converter can be seen as an attractive and cost competitive alternative to the Silicon Carbide based converter, also allowing to overcome the major drawbacks with the conventional Silicon IGBT...

  2. Urethane anesthesia depresses activities of thalamocortical neurons and alters its response to nociception in terms of dual firing modes

    Directory of Open Access Journals (Sweden)

    Yeowool eHuh

    2013-10-01

    Full Text Available Anesthetics are often used to characterize the activity of single neurons in-vivo for its advantages such as reduced noise level and convenience in noxious stimulations. Of the anesthetics, urethane had been widely used in some thalamic studies under the assumption that sensory signals are still relayed to the thalamus under urethane anesthesia and that thalamic response would therefore reflect the response of the awake state. We tested whether this assumption stands by comparing thalamic activity in terms of tonic and burst firing modes during ‘the awake state’ or under ‘urethane anesthesia’ utilizing the extracellular single unit recording technique. First we have tested how thalamic relay neurons respond to the introduction of urethane and then tested how urethane influences thalamic discharges under formalin-induced nociception. Urethane significantly depressed overall firing rates of thalamic relay neurons, which was sustained despite the delayed increase of burst activity over the 4 hour recording period. Thalamic response to nociception under anesthesia was also similar overall except for the slight and transient increase of burst activity. Overall, results demonstrated that urethane suppresses the activity of thalamic relay neurons and that, despite the slight fluctuation of burst firing, formalin-induced nociception cannot significantly change the firing pattern of thalamic relay neurons that was caused by urethane.

  3. Solar Charged Stand Alone Inverter

    OpenAIRE

    M.Vasugi; Prof R.Jayaraman

    2014-01-01

    This paper deals with solar powered stand alone inverter which converts the variable dc output of a photovoltaic solar panel into ac that can be fed to loads. Stand alone inverters are used in systems where the inverter get its energy from batteries charged by photo voltaic arrays. A charge controller limits the rate at which electric current is added to or drawn from electric batteries. This charge discharge controller is needed to prevent the battery from being overcharged o...

  4. Gas cooled traction drive inverter

    Science.gov (United States)

    Chinthavali, Madhu Sudhan

    2013-10-08

    The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

  5. Stability of Brillouin flow in planar, conventional, and inverted magnetrons

    International Nuclear Information System (INIS)

    Simon, D. H.; Lau, Y. Y.; Greening, G.; Wong, P.; Gilgenbach, R. M.; Hoff, B. W.

    2015-01-01

    The Brillouin flow is the prevalent flow in crossed-field devices. We systematically study its stability in the conventional, planar, and inverted magnetron geometry. To investigate the intrinsic negative mass effect in Brillouin flow, we consider electrostatic modes in a nonrelativistic, smooth bore magnetron. We found that the Brillouin flow in the inverted magnetron is more unstable than that in a planar magnetron, which in turn is more unstable than that in the conventional magnetron. Thus, oscillations in the inverted magnetron may startup faster than the conventional magnetron. This result is consistent with simulations, and with the negative mass property in the inverted magnetron configuration. Inclusion of relativistic effects and electromagnetic effects does not qualitatively change these conclusions

  6. Effect of Syngas Moisture Content on the Emissions of Micro-Gas Turbine Fueled with Syngas/LPG in Dual Fuel Mode

    Directory of Open Access Journals (Sweden)

    Sadig Hussain

    2014-07-01

    Full Text Available Syngas produced by gasification has a potential to be one of the fueling solutions for gas turbines in the future. In addition to the combustible constituents and inert gases, syngas derived by gasification contains a considerable amount of water vapor which effect on syngas combustion behaviour. In this work, a micro-gas turbine with a thermal capacity of 50 kW was simulated using ASPEN Plus. The micro gas turbine system emissions were characterized using dry syngas fuels with a different composition, syngas 1 (10.53% H2, 24.94% CO, 2.03% CH4, 12.80% CO2, and 49.70% N2 and syngas 2 (21.62% H2, 32.48% CO, 3.72% CH4, 19.69% CO2, and 22.49% N2 mixed with LPG in a dual fueling mode. The effect of syngas moisture content was then studied by testing the system with moist syngas/LPG with a moisture content ranging from 0 to 20% by volume. The study demonstrates that the syngas moisture content has high influence on nitrogen oxides and carbon monoxide emissions. It’s found that for 5% syngas moisture content, the NOx emission were reduced by 75.5% and 83% for Syngas 1 and Syngas 2 respectively. On carbon monoxide emissions and for same moisture content ratio, the reduction was found to be 43% and 57% for syngas1 and syngas 2 respectively.

  7. Perovskite photodetectors with both visible-infrared dual-mode response and super-narrowband characteristics towards photo-communication encryption application.

    Science.gov (United States)

    Wu, Ye; Li, Xiaoming; Wei, Yi; Gu, Yu; Zeng, Haibo

    2017-12-21

    Photo-communication has attracted great attention because of the rapid development of wireless information transmission technology. However, it is still a great challenge in cryptography communications, where it is greatly weakened by the openness of the light channels. Here, visible-infrared dual-mode narrowband perovskite photodetectors were fabricated and a new photo-communication encryption technique was proposed. For the first time, highly narrowband and two-photon absorption (TPA) resultant photoresponses within a single photodetector are demonstrated. The full width at half maximum (FWHM) of the photoresponse is as narrow as 13.6 nm in the visible range, which is superior to state-of-the-art narrowband photodetectors. Furthermore, these two merits of narrowband and TPA characteristics are utilized to encrypt the photo-communication based on the above photodetectors. When sending information and noise signals with 532 and 442 nm laser light simultaneously, the perovskite photodetectors only receive the main information, while the commercial Si photodetector responds to both lights, losing the main information completely. The final data are determined by the secret key through the TPA process as preset. Such narrowband and TPA detection abilities endow the perovskite photodetectors with great potential in future security communication and also provide new opportunities and platforms for encryption techniques.

  8. A 200-Channel Area-Power-Efficient Chemical and Electrical Dual-Mode Acquisition IC for the Study of Neurodegenerative Diseases.

    Science.gov (United States)

    Guo, Jing; Ng, Waichiu; Yuan, Jie; Li, Suwen; Chan, Mansun

    2016-06-01

    Microelectrode array (MEA) can be used in the study of neurodegenerative diseases by monitoring the chemical neurotransmitter release and the electrical potential simultaneously at the cellular level. Currently, the MEA technology is migrating to more electrodes and higher electrode density, which raises power and area constraints on the design of acquisition IC. In this paper, we report the design of a 200-channel dual-mode acquisition IC with highly efficient usage of power and area. Under the constraints of target noise and fast settling, the current channel design saves power by including a novel current buffer biased in discrete time (DT) before the TIA (transimpedance amplifier). The 200 channels are sampled at 20 kS/s and quantized by column-wise SAR ADCs. The prototype IC was fabricated in a 0.18 μm CMOS process. Silicon measurements show the current channel has 21.6 pArms noise with cyclic voltammetry (CV) and 0.48 pArms noise with constant amperometry (CA) while consuming 12.1 μW . The voltage channel has 4.07 μVrms noise in the bandwidth of 100 kHz and 0.2% nonlinearity while consuming 9.1 μW. Each channel occupies 0.03 mm(2) area, which is among the smallest.

  9. Report on preliminary study for promoting joint implementation in fiscal 1999. Feasibility study on introduction of dual mode bus system for reducing greenhouse effect gases in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    In order to discuss the possibility of adoption as the COP3 clean development mechanism, discussions were given in fiscal 1999 on the dual mode bus system (DMBS) in Malaysia. The DMBS combines the advantages of the track system such as monorails and the road system such as buses. On the dedicated roads, the DMBS forms ranks of buses which travel automatically. On ordinary roads, the ranks are separated into independent buses to cover an area in terms of a plane, with buses travelling for their respective destinations. Reduction in air resistance because of travelling at economic speeds and in ranks can save fuel and reduce CO2 emission. The DMBS can work effectively also in forming complementary relationship with the existing public transportation systems. Two routes have been set in the urban area of Kuala Lumpur, and discussions were given on the new town of Putra Jaya as the object. From the viewpoint of financial internal profitability, the possibility of establishing the system as a private business is low if it relies only on income from ticket sales because of high initial cost including development of infrastructures. The effects of CO2 reduction and energy conservation, and economic benefits would be brought about from the viewpoint of modal shift from privately owned automobiles to public transportation systems. (NEDO)

  10. Aalborg Inverter - A new type of “Buck in Buck, Boost in Boost” Grid-tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Blaabjerg, Frede

    2013-01-01

    This paper presents a new family of high efficiency DC/AC grid-tied inverter with a wide variation of input DC voltage. It is a kind of “Boost in Boost, Buck in Buck” inverter, meaning that only one power stage works at the high frequency to achieve the minimum switching loss. Furthermore......, the minimum filtering inductance in the power loop is achieved to reduce the conduction power loss whether in “Boost” or “Buck” mode. In theory, it can achieve higher efficiency than other inverters under the same condition of input DC voltage. The principle of operation is fully illustrated through...... the analysis on the equivalent circuits of a “three-level” single-phase inverter. Simulations show it has good control performance....

  11. 2015 Inverter Workshop | Photovoltaic Research | NREL

    Science.gov (United States)

    Inverter Workshop 2015 Inverter Workshop Wednesday, February 25, 2015 Chair: Jack Flicker In about inverters. This workshop represented a follow-on to the inverter workshops that Sandia National conversations between module and inverter experts. Agenda For a detailed schedule of the day's events, access

  12. Common voltage eliminating of SVM diode clamping three-level inverter connected to grid

    DEFF Research Database (Denmark)

    Guo, Yougui; Zeng, Ping; Zhu, Jieqiong

    2011-01-01

    A novel method of common voltage eliminating is put forward for SVM diode clamping three-level inverter connected to grid by calculation of common voltage of its various switching states. PLECS is used to model this three-level inverter connected to grid and good results are obtained. First...... analysis of common mode voltage for switching states of diode clamping 3-level inverter is given in detail. Second the common mode voltage eliminating control strategy of SVM is described for diode clamping three-level inverter. Third, PLECS is briefly introduced. Fourth, the modeling of diode clamping...... three-level inverter is presented with PLECS. Finally, a series of simulations are carried out. The simulation results tell us PLECS is a very powerful tool to real power circuits modeling. They have also verified that proposed common mode voltage eliminating control strategy of SVM is feasible...

  13. Embedded EZ-Source Inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Gao, F.

    2008-01-01

    -voltage oscillations to the system. Therefore, Z-source inverters are in effect safer and less complex, and can be implemented using only passive elements with no additional active semiconductor needed. Believing in the prospects of Z-source inverters, this paper contributes by introducing a new family of embedded EZ...

  14. Embedded EZ-Source Inverters

    DEFF Research Database (Denmark)

    Chiang Loh, Poh; Gao, Feng; Blaabjerg, Frede

    2010-01-01

    overvoltage oscillations to the system. Therefore, Z-source inverters are, in effect, safer and less complex and can be implemented using only passive elements with no additional active semiconductor needed. Believing in the prospects of Z-source inverters, this paper contributes by introducing a new family...

  15. Simplified High-Power Inverter

    Science.gov (United States)

    Edwards, D. B.; Rippel, W. E.

    1984-01-01

    Solid-state inverter simplified by use of single gate-turnoff device (GTO) to commutate multiple silicon controlled rectifiers (SCR's). By eliminating conventional commutation circuitry, GTO reduces cost, size and weight. GTO commutation applicable to inverters of greater than 1-kilowatt capacity. Applications include emergency power, load leveling, drives for traction and stationary polyphase motors, and photovoltaic-power conditioning.

  16. High efficiency inverter and ballast circuits

    International Nuclear Information System (INIS)

    Nilssen, O.K.

    1984-01-01

    A high efficiency push-pull inverter circuit employing a pair of relatively high power switching transistors is described. The switching on and off of the transistors is precisely controlled to minimize power losses due to common-mode conduction or due to transient conditions that occur in the process of turning a transistor on or off. Two current feed-back transformers are employed in the transistor base drives; one being saturable for providing a positive feedback, and the other being non-saturable for providing a subtractive feedback

  17. FET commutated current-FED inverter

    Science.gov (United States)

    Rippel, Wally E. (Inventor); Edwards, Dean B. (Inventor)

    1983-01-01

    A shunt switch comprised of a field-effect transistor (Q.sub.1) is employed to commutate a current-fed inverter (10) using thyristors (SCR1, SCR2) or bijunction transistors (Q.sub.2, Q.sub.3) in a full bridge (1, 2, 3, 4) or half bridge (5, 6) and transformer (T.sub.1) configuration. In the case of thyristors, a tapped inverter (12) is employed to couple the inverter to a dc source to back bias the thyristors during commutation. Alternatively, a commutation power supply (20) may be employed for that purpse. Diodes (D.sub.1, D.sub.2) in series with some voltage dropping element (resistor R.sub.12 or resistors R.sub.1, R.sub.2 or Zener diodes D.sub.4, D.sub.5) are connected in parallel with the thyristors in the half bridge and transformer configuration to assure sharing the back bias voltage. A clamp circuit comprised of a winding (18) negatively coupled to the inductor and a diode (D.sub.3) return stored energy from the inductor to the power supply for efficient operation with buck or boost mode.

  18. Electronic inverter assembly

    Science.gov (United States)

    Singh, Brij N.; Schmit, Christopher J.

    2018-05-22

    A first driver portion comprises a set of first components mounted on or associated with a first circuit board. A second circuit board is spaced apart from the first circuit board. A second driver portion comprises a set of second components mounted on or associated with the second circuit board, where the first driver portion and the second driver portion collectively are adapted to provide input signals to the control terminal of each semiconductor switch of an inverter. A first edge connector is mounted on the first circuit board. A second edge connector is mounted on the second circuit board. An interface board has mating edges that mate with the first edge connector and the second edge connector.

  19. A high control bandwidth design method for aalborg inverter under weak grid condition

    DEFF Research Database (Denmark)

    Wu, Weimin; Zhou, Cong; Wang, Houqin

    2017-01-01

    Aalborg Inverter is a kind of high efficient Buck-Boost inverter. Since it may work in “Buck-Boost” mode, the control bandwidth should be high enough to ensure a good performance under any grid condition. However, during the “Boost” operation, the control bandwidth depends much on the grid...

  20. Grid-Connected Inverter for Distributed Generation in Microgrid

    DEFF Research Database (Denmark)

    Naderipour, Amirreza; Miveh, Mohammad Reza; Guerrero, Josep M.

    for power generation. DGS units can operate in parallel to the main grid or in a Microgrid (MG) mode. An MG is a discrete energy system consisting of DGSs and loads capable of operating in parallel with, or independently from, the main grid. Meanwhile, Grid-Connected Inverters (GCIs) are typically used...

  1. A single phase photovoltaic inverter control for grid connected system

    Indian Academy of Sciences (India)

    operation the PV inverter operates in voltage-controlled mode to maintain a constant amplitude and frequency of the voltage ..... 10W i.e. less than 8% of the maximum power, a step size of k2 is ...... ply/demand side management system.

  2. An assessment of the dual-mode reactivity controlled compression ignition/conventional diesel combustion capabilities in a EURO VI medium-duty diesel engine fueled with an intermediate ethanol-gasoline blend and biodiesel

    International Nuclear Information System (INIS)

    Benajes, Jesús; García, Antonio; Monsalve-Serrano, Javier; Balloul, Iyad; Pradel, Gérard

    2016-01-01

    Highlights: • Reactivity controlled compression ignition regime utilized from 25% to 35% load. • Dual-mode reduces the regeneration periods of the diesel particulate filter. • The use of near-term available biofuels allows good performance and emissions. • Dual-mode leads to 2% greater efficiency than diesel combustion at high engine speeds. - Abstract: This work investigates the capabilities of the dual-mode reactivity controlled compression ignition/conventional diesel combustion engine operation to cover the full operating range of a EURO VI medium-duty diesel engine with compression ratio of 17.5:1. This concept is based on covering all the engine map switching between the reactivity controlled compression ignition and the conventional diesel combustion operating modes. Specifically, the benefits of reactivity controlled compression ignition combustion are exploited whenever possible according to certain restrictions, while the conventional diesel combustion operation is used to cover the zones of the engine map in which the reactivity controlled compression ignition operation is limited. The experiments were conducted using a single-cylinder research diesel engine derived from the multi-cylinder production engine. In addition, considering the mandatory presence of biofuels in the future context of road transport and the ability of ethanol to be blended with gasoline, the low reactivity fuel used in the study is a blend of 20% ethanol by volume with 80% of 95 octane number gasoline. Moreover, a diesel containing 7% of biodiesel has been used as high reactivity fuel. Firstly, a reactivity controlled compression ignition mapping is performed to check the operational limits of the concept in this engine platform. Later, based on the results, the potential of the dual-mode concept is discussed. Results suggest that, under the constraints imposed, reactivity controlled compression ignition combustion can be utilized between 25% and 35% load. In this region

  3. Analisis Harmonisa Inverter PWM Satu Fasa

    OpenAIRE

    Rejeki Simanjorang

    2008-01-01

    Pada tesis ini dianalisis harmonisa inverter PWM satu fasa. Inverter PWM satu fasa yang akan ditinjau adalah inverter satu fasa jembatan penuh (konvensional) dan inverter komposit. Analisis difokuskan pada penentuan pola penyaklaran yang optimum agar pembangkitan harmonisa dan switching losses inverter rendah. Untuk menentukan pola penyaklaran optimum maka dilakukan analisis yang berbasis pada rangkaian ekivalen harmonisa inverter satu fasa. Dengan menggunakan pola penyaklaran optimum, kedua ...

  4. Single phase cascaded H5 inverter with leakage current elimination for transformerless photovoltaic system

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Jia, X.; Lu, Z.

    2016-01-01

    Leakage current reduction is one of the important issues for the transformelress PV systems. In this paper, the transformerless single-phase cascaded H-bridge PV inverter is investigated. The common mode model for the cascaded H4 inverter is analyzed. And the reason why the conventional cascade H4...... inverter fails to reduce the leakage current is clarified. In order to solve the problem, a new cascaded H5 inverter is proposed to solve the leakage current issue. Finally, the experimental results are presented to verify the effectiveness of the proposed topology with the leakage current reduction...... for the single-phase transformerless PV systems....

  5. Single-stage MPPT control realization for Aalborg inverter in photovoltaic system

    DEFF Research Database (Denmark)

    Zhang, Shuai; Wu, Weimin; Wang, Houqing

    2017-01-01

    In this paper, the single-stage Maximum Power Point Tracking (MPPT) control strategy for the Aalborg photovoltaic inverter is presented. Aalborg inverter has many advantages, such as high efficiency, wide range of input voltage, minimum voltage drop of the filtering inductors, etc. Nevertheless......, it is essentially a “half-bridge” inverter with two input sources, where one source works in MPPT mode, the other is out of control. If without the reasonable parameter design and the proper control, the bus-voltage of this inverter may change greatly, resulting in the serious power oscillation around maximum power...

  6. LLCL-Filter Based Single-Phase Grid-Tied Aalborg Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Feng, Shuangshuang; Ji, Junhao

    2014-01-01

    The Aalborg Inverter is a new type of high efficient DC/AC grid-tied inverter, where the input DC voltage can vary in a wide range. Compared with the LCL-filter, the LLCL-filter can save the total inductance for the conventional voltage source inverter. In this paper, an LLCL-filter based Aalborg...... Inverter is proposed and its character is illustrated through the small signal analysis in both “Buck” and “Buck-Boost” mode. From the modeling, it can be seen that the resonant inductor in the capacitor loop has not brought extra control difficulties, whereas more inductance in the power loop can be saved...

  7. DUAL-MODE PROPULSION SYSTEM ENABLING CUBESAT EXPLORATION OF THE SOLAR SYSTEM NASA Innovative Advanced Concepts (NIAC) Phase I Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Nathan Jerred; Troy Howe; Adarsh Rajguru; Dr. Steven Howe

    2014-06-01

    It is apparent the cost of planetary exploration is rising as mission budgets declining. Currently small scientific beds geared to performing limited tasks are being developed and launched into low earth orbit (LEO) in the form of small-scale satellite units, i.e., CubeSats. These micro- and nano-satellites are gaining popularity among the university and science communities due to their relatively low cost and design flexibility. To date these small units have been limited to performing tasks in LEO utilizing solar-based power. If a reasonable propulsion system could be developed, these CubeSat platforms could perform exploration of various extra-terrestrial bodies within the solar system engaging a broader range of researchers. Additionally, being mindful of mass, smaller cheaper launch vehicles (~1,000 kgs to LEO) can be targeted. This, in effect, allows for beneficial explora-tion to be conducted within limited budgets. Researchers at the Center for Space Nuclear Re-search (CSNR) are proposing a low mass, radioisotope-based, dual-mode propulsion system capable of extending the exploration realm of these CubeSats out of LEO. The proposed radioisotope-based system would leverage the high specific energies [J/kg] associated with radioisotope materials and enhance their inherent low specific powers [W/g]. This is accomplished by accumulating thermal energy from nuclear decay within a central core over time. This allows for significant amounts of power to be transferred to a flowing gas over short periods of time. In the proposed configuration the stored energy can be utilized in two ways: (1) with direct propellant injection to the core, the energy can be converted into thrust through the use of a converging-diverging nozzle and (2) by flowing a working fluid through the core and subsequent Brayton engine, energy within the core can be converted to electrical energy. The first scenario achieves moderate ranges of thrust, but at a higher Isp than traditional chemical

  8. New model of inverting substation for DC traction with regenerative braking system

    Science.gov (United States)

    Omar, Abdul Malek Saidina; Samat, Ahmad Asri Abd; Isa, Siti Sarah Mat; Shamsuddin, Sarah Addyani; Jamaludin, Nur Fadhilah; Khyasudeen, Muhammad Farris

    2017-08-01

    This paper presents a power electronic devices application focus on modeling, analysis, and control of switching power converter in the inverting DC substation with regenerative braking system which is used to recycle the surplus regenerative power by feed it back to the main AC grid. The main objective of this research is to improve the switching power electronic converter of the railway inverting substation and optimize the maximum kinetic energy recovery together with minimum power losses from the railway braking system. Assess performance including efficiency and robustness will be evaluated in order to get the best solution for the design configuration. Research methodology included mathematical calculation, simulation, and detail analysis on modeling of switching power converter on inverting substation. The design stage separates to four main areas include rectification mode, regenerative mode, control inverter mode and filtering mode. The simulation result has shown that the regenerative inverter has a capability to accept a maximum recovery power on the regeneration mode. Total energy recovery has increase and power losses have decreases because inverter abilities to transfer the surplus energy back to the main AC supply. An Inverter controller with PWM Generator and PI Voltage Regulator has been designed to control voltage magnitude and frequency of the DC traction system.

  9. Cytosolic expression of functional Fab fragments in Escherichia coli using a novel combination of dual SUMO expression cassette and EnBase® cultivation mode.

    Science.gov (United States)

    Rezaie, F; Davami, F; Mansouri, K; Agha Amiri, S; Fazel, R; Mahdian, R; Davoudi, N; Enayati, S; Azizi, M; Khalaj, V

    2017-05-08

    The Escherichia coli expression system is highly effective in producing recombinant proteins. However, there are some limitations in this system, especially in obtaining correctly folded forms of some complex proteins such as Fab fragments. To improve the solubility and folding quality of Fab fragments, we have examined the effect of simultaneous application of a SUMO fusion tag, EnBase ® cultivation mode and a redox mutant strain in the E. coli expression system. A bicistronic gene construct was designed to express an antivascular endothelial growth factor (VEGF) Fab fragment as a model system. The construct contained a dual SUMO fusion gene fragment to encode SUMO-tagged heavy and light chains. While the expression of the construct in batch cultures of BL21 or SHuffle ® transformants produced insoluble and unfolded products, the induction of the transformants in EnBase ® medium resulted in soluble and correctly folded Fab fragment, reaching as high as 19% of the total protein in shuffle strain. The functional assays indicated that the biological activity of the target Fab is similar to the commercial anti-VEGF, Lucentis ® . This study demonstrated that the combination of SUMO fusion technology, EnBase ® cultivation system and recruiting a redox mutant of E. coli can efficiently enhance the solubility and productivity of recombinant Fab fragments. The presented strategy provides not only a novel method to produce soluble and active form of an anti-VEGF Fab but also may use in the efficient production of other antibody fragments. © 2017 The Society for Applied Microbiology.

  10. Predicting Vaccination Intention and Benefit and Risk Perceptions: The Incorporation of Affect, Trust, and Television Influence in a Dual-Mode Model.

    Science.gov (United States)

    Chen, Nien-Tsu Nancy

    2015-07-01

    Major health behavior change models tend to consider health decisions as primarily resulting from a systematic appraisal of relevant beliefs, such as the perceived benefits and risks of a pharmacological intervention. Drawing on research from the disciplines of risk management, communication, and psychology, this study proposed the inclusion of a heuristic route in established theory and tested the direction of influence between heuristic and systematic process variables. Affect and social trust were included as key heuristics in the proposed dual-mode framework of health decision making. Furthermore, exposure to health-related coverage on television was considered potentially influential over both heuristic and systematic process variables. To test this framework, data were collected from a national probability sample of 584 adults in the United States in 2012 regarding their decision to vaccinate against a hypothetical avian flu. The results provided some support for the bidirectional influence between heuristic and systematic processing. Affect toward flu vaccination and trust in the Food and Drug Administration were found to be powerful predictors of vaccination intention, enhancing intention both directly and indirectly via certain systematic process variables. The direction of influence between perceived susceptibility and severity, on the one hand, and affect, on the other, is less clear, suggesting the need for further research. Contrary to the opinion of media critics, exposure to televised health coverage was negatively associated with the perceived risks of vaccination. Results from this study carry theoretical and practical implications, and applying this model to the acceptance of different health interventions constitutes an area for future inquiries. © 2015 Society for Risk Analysis.

  11. Optimization of the composition of bimetallic core/shell Fe{sub 2}O{sub 3}/Au nanoparticles for MRI/CT dual-mode imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Song; Qi, Yueyong; Yang, Hua; Gong, Mingfu; Zhang, Dong; Zou, Liguang, E-mail: zlgxqyy@163.com [Third Military Medical University, Department of Radiology, Xinqiao Hospital (China)

    2013-11-15

    Bimetallic core/shell Fe{sub 2}O{sub 3}/Au nanoparticles are promising candidate dual-mode contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT) imaging. However, the gold coating on the hybrid nanoparticles (hybrids) affects the MRI and CT imaging quality. A thick gold nanoshell increases the X-ray attenuation effect but decreases the magnetic saturation of the hybrids. Therefore, we studied the effect of the Fe{sub 2}O{sub 3} and Au composition on these properties to find a suitable hybrid for MRI and CT imaging. Water-soluble, Au-coated magnetic nanoparticles were synthesized by iteratively reducing Au{sup 3+} onto the Fe{sub 2}O{sub 3} surface via hydroxylamine seeding. The properties of the hybrids obtained after different numbers of Au seeding cycles were studied using transmission electron microscopy, UV–Vis spectrophotometry, a vibrating swatch gaussmeter, MRI, CT, and an MTT assay. The hybrids obtained after three Au seeding cycles had an Fe{sub 2}O{sub 3}:Au molar ratio of 7.2:26.8, a mean diameter of 48.3 nm, a UV–Vis absorbance peak of 550 nm, a saturation magnetization of 49.0 emu/g, and no cytotoxicity at a concentration of 500 μg/mL after incubation with RAW 264.7 cells for up to 72 h. The hybrids obtained after three Au seeding cycles are the preferred candidates for MRI and CT applications because of their relatively high R2 relaxivity (95 mM{sup −1 }s{sup −1}) and X-ray attenuation (1.87 times that of iodine) compared to those of the other hybrids investigated in this study.

  12. Linear biocompatible glyco-polyamidoamines as dual action mode virus infection inhibitors with potential as broad-spectrum microbicides for sexually transmitted diseases

    Science.gov (United States)

    Mauro, Nicolò; Ferruti, Paolo; Ranucci, Elisabetta; Manfredi, Amedea; Berzi, Angela; Clerici, Mario; Cagno, Valeria; Lembo, David; Palmioli, Alessandro; Sattin, Sara

    2016-09-01

    The initial steps of viral infections are mediated by interactions between viral proteins and cellular receptors. Blocking the latter with high-affinity ligands may inhibit infection. DC-SIGN, a C-type lectin receptor expressed by immature dendritic cells and macrophages, mediates human immunodeficiency virus (HIV) infection by recognizing mannose clusters on the HIV-1 gp120 envelope glycoprotein. Mannosylated glycodendrimers act as HIV entry inhibitors thanks to their ability to block this receptor. Previously, an amphoteric, but prevailingly cationic polyamidoamine named AGMA1 proved effective as infection inhibitor for several heparan sulfate proteoglycan-dependent viruses, such as human papilloma virus HPV-16 and herpes simplex virus HSV-2. An amphoteric, but prevailingly anionic PAA named ISA23 proved inactive. It was speculated that the substitution of mannosylated units for a limited percentage of AGMA1 repeating units, while imparting anti-HIV activity, would preserve the fundamentals of its HPV-16 and HSV-2 infection inhibitory activity. In this work, four biocompatible linear PAAs carrying different amounts of mannosyl-triazolyl pendants, Man-ISA7, Man-ISA14, Man-AGMA6.5 and Man-AGMA14.5, were prepared by reaction of 2-(azidoethyl)-α-D-mannopyranoside and differently propargyl-substituted AGMA1 and ISA23. All mannosylated PAAs inhibited HIV infection. Both Man-AGMA6.5 and Man-AGMA14.5 maintained the HPV-16 and HSV-2 activity of the parent polymer, proving broad-spectrum, dual action mode virus infection inhibitors.

  13. Optimization of the composition of bimetallic core/shell Fe2O3/Au nanoparticles for MRI/CT dual-mode imaging

    International Nuclear Information System (INIS)

    Zhang, Song; Qi, Yueyong; Yang, Hua; Gong, Mingfu; Zhang, Dong; Zou, Liguang

    2013-01-01

    Bimetallic core/shell Fe 2 O 3 /Au nanoparticles are promising candidate dual-mode contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT) imaging. However, the gold coating on the hybrid nanoparticles (hybrids) affects the MRI and CT imaging quality. A thick gold nanoshell increases the X-ray attenuation effect but decreases the magnetic saturation of the hybrids. Therefore, we studied the effect of the Fe 2 O 3 and Au composition on these properties to find a suitable hybrid for MRI and CT imaging. Water-soluble, Au-coated magnetic nanoparticles were synthesized by iteratively reducing Au 3+ onto the Fe 2 O 3 surface via hydroxylamine seeding. The properties of the hybrids obtained after different numbers of Au seeding cycles were studied using transmission electron microscopy, UV–Vis spectrophotometry, a vibrating swatch gaussmeter, MRI, CT, and an MTT assay. The hybrids obtained after three Au seeding cycles had an Fe 2 O 3 :Au molar ratio of 7.2:26.8, a mean diameter of 48.3 nm, a UV–Vis absorbance peak of 550 nm, a saturation magnetization of 49.0 emu/g, and no cytotoxicity at a concentration of 500 μg/mL after incubation with RAW 264.7 cells for up to 72 h. The hybrids obtained after three Au seeding cycles are the preferred candidates for MRI and CT applications because of their relatively high R2 relaxivity (95 mM −1  s −1 ) and X-ray attenuation (1.87 times that of iodine) compared to those of the other hybrids investigated in this study

  14. Transformerless PV inverters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Borup, U.

    2009-12-15

    Since the start of the project the market for grid connected PV inverters have developed further. When the project started three - phase inverter were only available in high power systems. The technology developed within this project will enable three phase technology also to be implemented in string inverters for system down to 10 kW. We expect this to be very attractive due to the increased demand for symmetrical feed-in to the grid. The project relevance is therefore high and the sector continues to develop very much driven by technology. Especially the inverter technology is getting a lot of focus. The inverter systems are expected to take a much larger role in supporting the electrical grid in the future. The technology platform developed within the project is prepared to be extended with these utility functionalities. The main results of the project were: 1) A new technology concept for transformer-less inverters has been demonstrated with a number of prototypes. 2) Efficiency above 97,7% has been proven. 3) Efficiency and Maximum power point tracking has been optimized to ensure that almost all energy produced of the panels is transferred to the grid. 4) The platform is developed with a very fast control board, which enables extended functionality as demanding grid supporting functions in the future. Details about cost price and details about the control loop implementation is excluded from the report due to the competitive situation for Danfoss Solar Inverters A/S. (LN)

  15. Nonlinear analysis of a family of LC tuned inverters. [dc to square wave circuits for power conditioning

    Science.gov (United States)

    Lee, F. C. Y.; Wilson, T. G.

    1974-01-01

    A family of four dc-to-square-wave LC tuned inverters are analyzed using singular point. Limit cycles and waveshape characteristics are given for three modes of oscillation: quasi-harmonic, relaxation, and discontinuous. An inverter in which the avalanche breakdown of the transistor emitter-to-base junction occurs is discussed and the starting characteristics of this family of inverters are presented. The LC tuned inverters are shown to belong to a family of inverters with a common equivalent circuit consisting of only three 'series' elements: a five-segment piecewise-linear current-controlled resistor, linear inductor, and linear capacitor.

  16. Module Embedded Micro-inverter Smart Grid Ready Residential Solar Electric System

    Energy Technology Data Exchange (ETDEWEB)

    Agamy, Mohammed [GE Global Research Center, Niskayuna, NY (United States)

    2015-10-27

    The “Module Embedded Micro-inverter Smart Grid Ready Residential Solar Electric System” program is focused on developing innovative concepts for residential photovoltaic (PV) systems with the following objectives: to create an Innovative micro-inverter topology that reduces the cost from the best in class micro-inverter and provides high efficiency (>96% CEC - California Energy Commission), and 25+ year warranty, as well as reactive power support; integrate micro-inverter and PV module to reduce system price by at least $0.25/W through a) accentuating dual use of the module metal frame as a large area heat spreader reducing operating temperature, and b) eliminating redundant wiring and connectors; and create micro-inverter controller handles smart grid and safety functions to simplify implementation and reduce cost.

  17. Modulation of Current Source Inverter

    Directory of Open Access Journals (Sweden)

    Golam Reza Arab Markadeh

    2011-04-01

    Full Text Available Direct torque control with Current Source Inverter (CSI instead of voltage source inverter is so appropriate because of determining the torque of induction motor with machine current and air gap flux. In addition, Space-Vector Modulation (SVM is a more proper method for CSI because of low order harmonics reduction, lower switching frequency and easier implementation. This paper introduces the SVM method for CSI and uses the proposed inverter for vector control of an induction motor. The simulation results illustrate fast dynamic response and desirable torque and speed output. Fast and accurate response to changes of speed and load torque reference completely proves the prominence of this method.

  18. Dual Mode Slotted Monopole Antenna

    Science.gov (United States)

    2017-01-05

    May 2017 The below identified patent application is available for licensing. Requests for information should be addressed to: TECHNOLOGY...REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention is directed...to connect across slot 14. [0005] In United States Patent No. 6,127,983 to Rivera and Josypenko, it has been shown that the slotted cylinder

  19. Aalborg Inverter - A New Type of “Buck in Buck, Boost in Boost” Grid-Tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Ji, Junhao; Blaabjerg, Frede

    2015-01-01

    This paper presents a new family of high efficiency dc/ac grid-tied inverter with a wide variation of input dc voltage. It is a “boost in boost, buck in buck” inverter, meaning that only one power stage works at high frequency in order to achieve minimum switching loss. The minimum voltage drop...... of the filtering inductor in the power loop is achieved to reduce the conduction power loss in both “boost” and “buck” mode. The principle of operation is demonstrated through the analysis on the equivalent circuits of a “half-bridge” single-phase inverter. The theoretical analysis shows that when input dc voltage...... is larger than the magnitude of the ac voltage, it is a voltage-source inverter, and on the contrary it is current-source inverter in the other mode. A 220 V/50 Hz/ 2000 W prototype has been constructed. Simulations and experiments show that it has a good control and system performance....

  20. Short-term precision assessment of trabecular bone score and bone mineral density using dual-energy X-ray absorptiometry with different scan modes: an in vivo study

    Energy Technology Data Exchange (ETDEWEB)

    Bandirali, Michele; Poloni, Alessandro; Messina, Carmelo; Petrini, Marcello [Universita degli Studi di Milano, Scuola di Specializzazione in Radiodiagnostica, Milano (Italy); Sconfienza, Luca Maria; Sardanelli, Francesco [Unita di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese (Italy); Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, San Donato Milanese (Italy); Papini, Giacomo Davide Edoardo; Di Leo, Giovanni [Unita di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese (Italy); Ulivieri, Fabio Massimo [IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, Mineralometria Ossea Computerizzata e Ambulatorio Malattie Metabolismo Minerale e Osseo, Servizio di Medicina Nucleare, Milano (Italy)

    2015-07-15

    We estimated the in vivo reproducibility of trabecular bone score (TBS) from dual-energy X-ray absorptiometry (DXA) using different imaging modes to be compared to that of bone mineral density (BMD). We enrolled 30 patients for each imaging mode: fast-array, array, high definition. Each patient underwent two DXA examinations with in-between repositioning. BMD and TBS were obtained according to the International Society for Clinical Densitometry guidelines. The coefficient of variation (CoV) was calculated as the ratio between root mean square standard deviation and mean, percent least significant change (LSC) as 2.77 x CoV, reproducibility as the complement to 100 % LSC. Fast-array imaging mode resulted in 0.8 % CoV and 2.1 % LSC for BMD, 1.9 % and 5.3 % for TBS, respectively; array imaging mode resulted in 0.7 % and 2.0 % for BMD, 1.9 % and 5.2 %, for TBS; high-definition imaging mode resulted in 0.7 % and 2.0 %, for BMD; 2.0 % and 5.4 % for TBS, respectively. Reproducibility of TBS (95 %) was significantly lower than that of BMD (98 %) (p < 0.012). Difference in reproducibility among the imaging modes was not significant for either BMD or TBS (p = 0.942). While TBS reproducibility was significantly lower than that of BMD, differences among imaging modes were not significant for both TBS and BMD. (orig.)

  1. Nanowire NMOS Logic Inverter Characterization.

    Science.gov (United States)

    Hashim, Yasir

    2016-06-01

    This study is the first to demonstrate characteristics optimization of nanowire N-Channel Metal Oxide Semiconductor (NW-MOS) logic inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. A computer-based model used to produce static characteristics of NW-NMOS logic inverter. In this research two circuit configuration of NW-NMOS inverter was studied, in first NW-NMOS circuit, the noise margin for (low input-high output) condition was very low. For second NMOS circuit gives excellent noise margins, and results indicate that optimization depends on applied voltage to the inverter. Increasing gate to source voltage with (2/1) nanowires ratio results better noise margins. Increasing of applied DC load transistor voltage tends to increasing in decreasing noise margins; decreasing this voltage will improve noise margins significantly.

  2. Fabricating an organic complementary inverter by integrating two transistors on a single substrate

    International Nuclear Information System (INIS)

    Wang Jun; Wei Bin; Zhang Jianhua

    2008-01-01

    Organic complementary inverters were fabricated by integrating two transistors of different electric type on a single substrate. One is a p-type organic heterojunction transistor with a depletion–accumulation mode that acts as a load element. The other is an n-type transistor with an accumulation mode that acts as a drive element. Typical inverter characteristics with a voltage gain of 12 were obtained. Compared with conventional devices, our organic complementary inverter used only one-step patterning of an organic semiconductor, and simultaneously suppressed the leakage current between supply voltage and ground. Therefore, current studies provide a simpler path to fabrication of organic complementary circuits

  3. Droop-Controlled Inverters with Seamless Transition between Islanding and Grid-Connected Operations

    DEFF Research Database (Denmark)

    Hu, Shang-Hung; Kuo, Chun-Yi; Lee, Tzung-Lin

    2011-01-01

    This paper presents a seamless transition method for droop-controlled inverters to operate in both islanding and grid-connected modes. A local PLL and a virtual inductance are designed to ride through transient when the inverter switches between two modes with no synchronization. The proposed...... method can cooperatively work with well-developed droop controls so that the inverters are able to share load among them as well as subsist under transient events of the utility. Theoretical analysis and experimental results validate effectiveness of the proposed method....

  4. Coronary artery stent imaging with 128-slice dual-source CT using high-pitch spiral acquisition in a cardiac phantom: comparison with the sequential and low-pitch spiral mode

    International Nuclear Information System (INIS)

    Wolf, Florian; Loewe, Christian; Plank, Christina; Schernthaner, Ruediger; Bercaczy, Dominik; Lammer, Johannes; Leschka, Sebastian; Goetti, Robert; Marincek, Borut; Alkadhi, Hatem; Homolka, Peter; Friedrich, Guy; Feuchtner, Gudrun

    2010-01-01

    To evaluate coronary stents in vitro using 128-slice-dual-source computed tomography (CT). Twelve different coronary stents placed in a non-moving cardiac/chest phantom were examined by 128-slice dual-source CT using three CT protocols [high-pitch spiral (HPS), sequential (SEQ) and conventional spiral (SPIR)]. Artificial in-stent lumen narrowing (ALN), visible inner stent area (VIA), artificial in-stent lumen attenuation (ALA) in percent, image noise inside/outside the stent and CTDIvol were measured. Mean ALN was 46% for HPS, 44% for SEQ and 47% for SPIR without significant difference. Mean VIA was similar with 31% for HPS, 30% for SEQ and 33% for SPIR. Mean ALA was, at 5% for HPS, significantly lower compared with -11% for SPIR (p = 0.024), but not different from SEQ with -1%. Mean image noise was significantly higher for HPS compared with SEQ and SPIR inside and outside the stent (p < 0.001). CTDIvol was lower for HPS (5.17 mGy), compared with SEQ (9.02 mGy) and SPIR (55.97 mGy), respectively. The HPS mode of 128-slice dual-source CT yields fewer artefacts inside the stent lumen compared with SPIR and SEQ, but image noise is higher. ALN is still too high for routine stent evaluation in clinical practice. Radiation dose of the HPS mode is markedly (less than about tenfold) reduced. (orig.)

  5. Transformerless photovoltaic inverters with leakage current and pulsating power elimination

    DEFF Research Database (Denmark)

    Tang, Yi; Yao, Wenli; Wang, H.

    2015-01-01

    This paper presents a transformerless inverter topology, which is capable of simultaneously solving leakage current and pulsating power issues in grid-connected photovoltaic (PV) systems. Without adding any additional components to the system, the leakage current caused by the PV......-to-ground parasitic capacitance can be bypassed by introducing a common mode (CM) conducting path to the inverter. The resulting ground leakage current is therefore well controlled to be below the regulation limit. Moreover, the proposed inverter can also eliminate the well-known double line frequency pulsating power....... The mechanism of leakage current suppression and the closed-loop control of pulsating power decoupling are discussed in the paper in details. A 500 W prototype was also built and tested in the laboratory, and both simulation and experimental results are finally presented to show the excellent performance...

  6. Hydrodynamic stability of inverted annular flow in an adiabatic simulation

    International Nuclear Information System (INIS)

    De Jarlais, G.; Ishii, M.; Linehan, J.

    1986-01-01

    Inverted annular flow was simulated adiabatically with turbulent water jets, issuing downward from large aspect ratio nozzles, enclosed in gas annuli. Velocities, diameters, and gas species were varied, and core jet length, shape, breakup mode, and dispersed core droplet sizes were recorded at approximately 750 data points. Inverted annular flow destabilization led to inverted slug flow at low relative velocities, and to dispersed droplet flow, core breakup length correlations were developed by extending work on free liquid jets to include this coaxial, jet disintegration phenomenon. The results show length dependence upon D/sub J/, Re/sub J/, We/sub J/, α, and We/sub G/,rel. Correlations for core shape, breakup mechanisms, and dispersed core droplet size were also developed, by extending the results of free jet stability, roll wave entrainment, and churn turbulent droplet stability studies

  7. Γ-source Neutral Point Clamped Inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Blaabjerg, Frede

    Transformer based Z-source inverters are recently proposed to achieve promising buck-boost capability. They have improved higher buck-boost capability, smaller size and less components count over Z-source inverters. On the other hand, neutral point clamped inverters have less switching stress...... and better output performance comparing with traditional two-level inverters. Integrating these two types of configurations can help neutral point inverters achieve enhanced votlage buck-boost capability....

  8. Dual Mode Vehicle with In-Wheel Motor: Regenerative Braking Optimization Véhicule bi-mode avec moteurs roues : optimisation du freinage récupératif

    Directory of Open Access Journals (Sweden)

    Le Solliec G.

    2013-03-01

    Full Text Available To meet the growing need for mobility of people and goods while massively reducing CO2 emissions, the electrification of vehicles is an essential solution. The variety of vehicles and their use results in innovative solutions for adapted architecture. This is especially true for light commercial vehicles where the objective is to promote full electric use in urban conditions (zero emission vehicle while maintaining significant range autonomy on road. The project VelRoue, a partnership between Renault, Michelin and IFP Energies nouvelles, aims to develop a dedicated dual-mode vehicle using a conventional thermal powertrain on the front axle and in-wheel motors on the rear one each powertrain to its use and makes it possible to achieve a low level of homologation CO2 emissions. In addition to features that meet the specific use of a commercial vehicle, in this paper we will particularly demonstrate the benefit of such an architecture to optimize the regenerative braking while ensuring a safe dynamic behaviour. Pour faire face au besoin croissant de mobilité des personnes et des biens tout en réduisant massivement les émissions de CO2, l’électrification des véhicules est une solution majeure. La grande variété des véhicules et de leur utilisation conduit à la mise en place d’architectures adaptées et donc de solutions innovantes. Cela est particulièrement le cas pour le développement de véhicules utilitaires dont l’objectif est de promouvoir un usage tout électrique en ville (véhicule zéro émission tout en maintenant une autonomie significative pour un usage extra-urbain. Le projet VelRoue, un partenariat entre Renault, Michelin et IFP Energies nouvelles, a pour objectif le développement d’un véhicule utilitaire bi-mode utilisant un groupe motopropulseur thermique traditionnel sur le train avant et des moteurs roues sur le train arrière. Chaque système de propulsion sera alors séparément optimisé à son utilisation

  9. Inverted emulsion drilling fluid

    Energy Technology Data Exchange (ETDEWEB)

    Ana, I; Astanei, E; Mireanu, G; Orosz, M; Popescu, F; Vasile, I

    1979-07-28

    The subject of the invention is the method of obtaining inverted drilling fluid which is required during stripping of a productive bed and ending of a well where difficulties develop during drilling of the argillaceous rock. Example: in a reservoir with capacity 30 m/sup 3/, 10 m/sup 3/ of diesel fuel are added. A total of 1000 kg of emulsifier are added to the diesel fuel consisting of: 85 mass% of a mixture of sodium and potassium salts of fatty acids, residues of fatty acids or naphthene acids with high molecular weight taken in proportion of 10:90; 5 mass% of a mixture of polymers with hydrophilic-hydrophobic properties obtained by mixing 75 mass% of polyethylene oxide with molecular weight 10,000 and 25 mass% of propylene oxide with molecular weight 15,000, and 10 mass% of salt on alkaline earth metal (preferably calcium chloride). The mixture is mixed into complete dissolving. Then 1200 kg of filtering accelerator are added obtained from concentrated sulfuric acid serving for sulfur oxidation, asphalt substance with softening temperature 85-104/sup 0/C and fatty acids C/sub 10/-C/sub 20/ taken in a proportion of 23.70 and 7 mass% The mixture obtained in this manner is neutralized by adding calcium hydroxide and equal quantities of alumina and activated bentonite clay in a concentration of 1-10 mass%, more preferably 5 mass% in relation to the initial mixture. The obtained mass is mixed until complete dispersion, after which 200 kg of organophilic clay are added obtained from bentonite of the type montmorillonite of sodium by processing with derivate obtained from amine of the type of the quaternary base of ammonium salt, and agent of hydrophobization of the type of fatty alcohols, fatty acids, nonion surfactants of the block-polymer type. After complete dispersion of the organophilic clay, 100 kg of stabilizer of emulsion of the surfactant type was added with molecular weight of 250010,000, more preferably 5000, in concentration of 0.1-5.0 mass%, more

  10. Fiscal 1999 report on basic research for promotion of joint implementation programs. Research on introduction of dual mode bus system for greenhouse gas reduction; 1999 nendo onshitsu koka gas sakugen no tame no dual mode bus system donyu ni kansuru chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    A feasibility study is conducted of the above-named system in Malaysia, to be linked to COP3 (Third Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change) clean development mechanism (CDM). The dual mode bus system (DMBS) is a combination of advantages of the rail running stock such as monorails and the road running stock in that the buses when running on dedicated roads are automatedly formed into a linear formation and travel at a specified economical speed. When running on ordinary roads, the formation is broken into individual buses, and they spread in the town where they travel in a planar pattern. The economical speed and reduction in air drag thanks to the linear formation saves fuel and reduces CO2 emissions. The complementary relationship to be formed with the existing public transportation systems will also function positively. Studies are conducted on condition that two routes be laid in the Kuala Lumpur urban area and one in the new city Putra Jaya. All the three routes exhibit a high economic internal rate of return, but their financial internal rate of return indicates that probabilities are low that they will pay as private businesses. They will need financial supports such as subsidies. Contribution to CO2 reduction may be slight when attention is paid only to the partial changeover from the existing bus system to DMBS but larger contribution will be found in crossover from private cars to DMBS which is higher in quality of service. (NEDO)

  11. Design of inverters for the PHOTONERGY project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-08-01

    The PHOTONERGY project (the former SolcelleInverter project) was initiated on the 1st of September 2001, with a state-of-the-art analysis, which concluded into specifications. Based on this 23 topologies were analyzed in for efficiencies. The results from this analysis was five candidates which all showed a somewhat good efficiency. These five topologies were in further investigated by means of an initial design-iteration and simulations. Two different solutions were picked up in due to their high efficiency and low cost. 1. The standard full-bridge phase shifted DC/DC converter together with a standard DC/AC inverter, 2. A modified version of the novel Shimizu topology. A patent is pending on this modified version. These two inverters are in this document developed and made ready for prototyping. This includes design and selection of reactive- and switching-components, e.g. filter- and bulk-capacitors, low- and high-frequency inductors, high frequency transformers, MOSFETs and diodes. The design of auxiliary circuits is also included, e.g. gate drivers for the MOSFETs, measuring circuits for the grid-current and -voltage, PV-module-current and voltage, protection circuits, hardware near controllers and finally a switch mode power supply. However, the design of the various controllers, except the hardware near PV-current controller for the full bridge phase shifted converter, is not documented in this report but will come later on. This includes all controllers, e.g. maximum power point tracking for the PV-module, utility grid current controller, DC-link voltage controller, phase locked loops, and detection of islanding operation. All of these control loops are to be implemented in a micro-controller. (au)

  12. Preparation of inverted medium and processing in the inverted medium

    International Nuclear Information System (INIS)

    Zafarullah, Ijaz; Tian Minghzen; Chang Tiejun; Randall Babbitt, W.

    2007-01-01

    The processing of weak optical signals in spatial-spectral holographic (SSH) materials coherently inverted with optical frequency chirped pulses were investigated. Simulations and experimental studies in Tm 3+ :YAG were conducted to characterize the parameters of the frequency chirped laser pulse used to invert the SSH material in order to obtain high photon echo efficiency for SSH lidar processing. Collinear and angled beam geometries and single shot and accumulated processes were investigated. Echo efficiencies as high as 450% were measured, significantly higher than the typical stimulated photon echo efficiency of 10%

  13. Preparation of inverted medium and processing in the inverted medium

    Energy Technology Data Exchange (ETDEWEB)

    Zafarullah, Ijaz [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)]. E-mail: ijaz@montana.edu; Tian Minghzen [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Chang Tiejun [The Spectrum Laboratory, Montana State University, Bozeman, MT 59717 (United States); Randall Babbitt, W. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2007-11-15

    The processing of weak optical signals in spatial-spectral holographic (SSH) materials coherently inverted with optical frequency chirped pulses were investigated. Simulations and experimental studies in Tm{sup 3+}:YAG were conducted to characterize the parameters of the frequency chirped laser pulse used to invert the SSH material in order to obtain high photon echo efficiency for SSH lidar processing. Collinear and angled beam geometries and single shot and accumulated processes were investigated. Echo efficiencies as high as 450% were measured, significantly higher than the typical stimulated photon echo efficiency of 10%.

  14. 陕西电信天翼3G双模智能机市场发展策略研究%Shanxi Telecom Tianyi 3G Dual-mode Intelligent Machine Market Development Strategy Research

    Institute of Scientific and Technical Information of China (English)

    贾琳

    2013-01-01

    中国电信陕西公司天翼3G智能终端销售在2011年至2012年间快速上升,但2012年下半年,智能机发展出现阶段性波动,增长率降低;同时竞争对手发力双模智能机,快速挖转中国移动用户。分析和论证发展天翼3G双模智能机的必要性,并从产品、价格、渠道、宣传和促销4方面提出了天翼3G双模智能机发展的具体策略,对于陕西电信进一步加快智能机的发展,拓展社会开放渠道,保持3G市场领先优势具有重要意义。%3G intelligent terminal sales of Shaanxi China Telecom Tianyi form 2011 to 2012 years the rises rapidly,but the second half of 2012, intelligent machine development stage of volatility, growth rate decreased,rival force of dual-mode intelligent machine, fast digging to China Mobile users at the same time. This paper focuses on a telecommunications enterprise employee's point of view, fully aware of the changing market environment and competition strategy, the necessity analysis and demonstration of development day wing 3G dual-mode intelligent machines, and specific strategies day wing development 3G dual-mode intelligent machine is put forward from the product, price, channel, promotion and promotion four aspects, for Shaanxi to further accelerate the development of the telecom intelligent machine, expand social open channel, it is important to keep the 3G market advantage.

  15. Self-starting and overclocking a harmonically mode-locking WRC-FPLD with a dual-loop feedback controller for 10 Gb s−1 pulse-data transmission

    International Nuclear Information System (INIS)

    Lin, Chun-Ju; Chi, Yu-Chieh; Lin, Gong-Ru

    2013-01-01

    The self-starting and overclocking of a harmonically mode-locked weak-resonant-cavity Fabry–Perot laser diode (WRC-FPLD) with a dual-loop coupled optoelectronic oscillator (COEO) based feedback controller is demonstrated to perform a clock-free pulsed data transmission at 10 Gb s −1 . The WRC-FPLD is considered as the preferred candidate for harmonic mode-locking due to its highly asymmetric cavity architecture, whereby the spontaneous noise can be significantly suppressed without inducing large intra-cavity loss. With the dual-loop COEO configuration, the WRC-FPLD can be boosted to four times of its original modulation bandwidth such that the pulsed carrier quality can be refined. The structure-optimizing principle with the closed-loop model is corroborated by the effective spurious-noise-suppression. The lowest phase noises as low as −100 dBc Hz −1 at 10 kHz with corresponding RMS timing jitter of 0.67 ps are measured. This is achieved by individually inserting 100 and 120 m long single mode fiber segments into two decoupled arms, the dual-loop COEO before the optical receiver pair. The BER performance reaches a minimum with the optimized SMF segment lengths. However, the spurious peaks arise to degrade the BER performance as the phase noise and jitter are inevitably enlarged when inserting longer SMF segments. After modulating the optimized output pulse train with the pseudo-random-bit-sequence data triggered by the same COEO clock, the SNR can achieve 10.9 dB and the receiving sensitivity is −19.2 dBm. (letter)

  16. Smart Inverter Control and Operation for Distributed Energy Resources

    Science.gov (United States)

    Tazay, Ahmad F.

    The motivation of this research is to carry out the control and operation of smart inverters and voltage source converters (VSC) for distributed energy resources (DERs) such as photovoltaic (PV), battery, and plug-in hybrid electric vehicles (PHEV). The main contribution of the research includes solving a couple of issues for smart grids by controlling and implementing multifunctions of VSC and smart inverter as well as improving the operational scheme of the microgrid. The work is mainly focused on controlling and operating of smart inverter since it promises a new technology for the future microgrid. Two major applications of the smart inverter will be investigated in this work based on the connection modes: microgrid at grid-tied mode and autonomous mode. In grid-tied connection, the smart inverter and VSC are used to integrate DER such as Photovoltaic (PV) and battery to provide suitable power to the system by controlling the supplied real and reactive power. The role of a smart inverter at autonomous mode includes supplying a sufficient voltage and frequency, mitigate abnormal condition of the load as well as equally sharing the total load's power. However, the operational control of the microgrid still has a major issue on the operation of the microgrid. The dissertation is divided into two main sections which are: 1. Low-level control of a single smart Inverter. 2. High-level control of the microgrid. The first part investigates a comprehensive research for a smart inverter and VSC technology at the two major connections of the microgrid. This involves controlling and modeling single smart inverter and VSC to solve specific issues of microgrid as well as improve the operation of the system. The research provides developed features for smart inverter comparing with a conventional voltage sourced converter (VSC). The two main connections for a microgrid have been deeply investigated to analyze a better way to develop and improve the operational procedure of

  17. Accelerating development of advanced inverters :

    Energy Technology Data Exchange (ETDEWEB)

    Neely, Jason C.; Gonzalez, Sigifredo; Ropp, Michael; Schutz, Dustin

    2013-11-01

    The high penetration of utility interconnected photovoltaic (PV) systems is causing heightened concern over the effect that variable renewable generation will have on the electrical power system (EPS). These concerns have initiated the need to amend the utility interconnection standard to allow advanced inverter control functionalities that provide: (1) reactive power control for voltage support, (2) real power control for frequency support and (3) better tolerance of grid disturbances. These capabilities are aimed at minimizing the negative impact distributed PV systems may have on EPS voltage and frequency. Unfortunately, these advanced control functions may interfere with island detection schemes, and further development of advanced inverter functions requires a study of the effect of advanced functions on the efficacy of antiislanding schemes employed in industry. This report summarizes the analytical, simulation and experimental work to study interactions between advanced inverter functions and anti-islanding schemes being employed in distributed PV systems.

  18. Inverter design for high frequency power distribution

    Science.gov (United States)

    King, R. J.

    1985-01-01

    A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

  19. Study on model current predictive control method of PV grid- connected inverters systems with voltage sag

    Science.gov (United States)

    Jin, N.; Yang, F.; Shang, S. Y.; Tao, T.; Liu, J. S.

    2016-08-01

    According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

  20. Experimental study of inverted-annular-flow hydrodynamics utilizing an adiabatic simulation

    International Nuclear Information System (INIS)

    De Jarlais, G.

    1983-03-01

    In experiments, inverted annular flow was simulated adiabatically with turbulent water jets, issuing downward from long aspect nozzles, enclosed in gas annuli. Velocities, diameters, and gas species were varied, and core jet length, shape, break-up mode, and dispersed-core droplet sizes were recorded at approximately 750 data points. Inverted annular flow was observed to develop into inverted slug flow at low relative velocities, and into dispersed droplet flow at high relative velocities. For both of the above transitions from inverted annular flow, correlations for core jet length were developed by extending work done on free liquid jets to include this new, coaxial, jet disintegration phenomenon. Jet break-up length is correlated as a function of jet diameter, jet Reynolds number, jet Weber number, void fraction, and gas Weber number. Correlations for core shape, break-up mechanisms and dispersed core droplet size for the case of transition to inverted slug flow were developed

  1. Bullet Design and Fabrication of Dual Mode Pyroelectric Sensor: High Sensitive Energymeter for Nd: YAG Laser and Detector for Chopped He-Ne Laser

    Directory of Open Access Journals (Sweden)

    S. SATAPATHY

    2008-05-01

    Full Text Available Pyroelectric sensor using TGS has been designed and fabricated which can be operated in laser energy meter mode as well as pyroelectric detector mode. The amplifying circuit configuration has very good signal to noise ratio, very high input impedance and low drift. The pyroelectric sensor has been tested using Q-switched Nd: YAG laser and chopped He-Ne laser. The sensitivity of pyroelectric sensor in energymeter mode is 421.7V/J and the voltage responsivity of the pyroelectric sensor is 3.27 V/W in detector mode.

  2. Inverters for photovoltaics: quality assurance

    International Nuclear Information System (INIS)

    Graf, J.D.; Haeberlin, H.

    2000-01-01

    This project-overview published by the University of Applied Science in Burgdorf, Switzerland, looks back at the history of the university's testing laboratory for inverters for use in photovoltaic installations and discusses the work done there. After its move from Oberburg to Burgdorf in the early nineties, the laboratory was equipped to provide testing facilities for inverters up to 60 kW. Additions have been made to the infrastructure since then to facilitate the testing of various types of inverter produced in Switzerland and other countries. The measurements that can be carried out, including DC-AC conversion efficiency, harmonics, RF interference, islanding, sensitivity to tele-control signals, turn-on power and operating voltage range are described. The improvement in the quality of the inverters tested is discussed and the importance of continued testing as new manufacturers come onto the market is emphasised. The installation of further testing equipment, such as a 25 kW solar generator simulator and apparatus for the testing of maximum-power-tracking efficiency is discussed

  3. Inverting an Introductory Statistics Classroom

    Science.gov (United States)

    Kraut, Gertrud L.

    2015-01-01

    The inverted classroom allows more in-class time for inquiry-based learning and for working through more advanced problem-solving activities than does the traditional lecture class. The skills acquired in this learning environment offer benefits far beyond the statistics classroom. This paper discusses four ways that can make the inverted…

  4. Phase synchronized quasiperiodicity in power electronic inverter systems

    DEFF Research Database (Denmark)

    Zhusubaliyev, Zhanybai T.; Mosekilde, Erik; Andriyanov, Alexey I.

    2014-01-01

    The development of switch-mode operated power electronic converter systems has provided a broad range of new effective approaches to the conversion of electric power. In this paper we describe the transitions from regular periodic operation to quasiperiodicity and high-periodic resonance behavior...... findings are verified through comparison with an experimental inverter system. The results shed light on the transitions to quasiperiodicity and to various forms of three-frequency dynamics in non-smooth systems....

  5. Overload protection system for power inverter

    Science.gov (United States)

    Nagano, S. (Inventor)

    1977-01-01

    An overload protection system for a power inverter utilized a first circuit for monitoring current to the load from the power inverter to detect an overload and a control circuit to shut off the power inverter, when an overload condition was detected. At the same time, a monitoring current inverter was turned on to deliver current to the load at a very low power level. A second circuit monitored current to the load, from the monitoring current inverter, to hold the power inverter off through the control circuit, until the overload condition was cleared so that the control circuit may be deactivated in order for the power inverter to be restored after the monitoring current inverter is turned off completely.

  6. Membrane fusion and inverted phases

    International Nuclear Information System (INIS)

    Ellens, H.; Siegel, D.P.; Alford, D.; Yeagle, P.L.; Boni, L.; Lis, L.J.; Quinn, P.J.; Bentz, J.

    1989-01-01

    We have found a correlation between liposome fusion kinetics and lipid phase behavior for several inverted phase forming lipids. N-Methylated dioleoylphosphatidylethanolamine (DOPE-Me), or mixtures of dioleoylphosphatidylethanolamine (DOPE) and dioleoylphosphatidylcholine (DOPC), will form an inverted hexagonal phase (HII) at high temperatures (above TH), a lamellar phase (L alpha) at low temperatures, and an isotropic/inverted cubic phase at intermediate temperatures, which is defined by the appearance of narrow isotropic 31 P NMR resonances. The phase behavior has been verified by using high-sensitivity DSC, 31 P NMR, freeze-fracture electron microscopy, and X-ray diffraction. The temperature range over which the narrow isotropic resonances occur is defined as delta TI, and the range ends at TH. Extruded liposomes (approximately 0.2 microns in diameter) composed of these lipids show fusion and leakage kinetics which are strongly correlated with the temperatures of these phase transitions. At temperatures below delta TI, where the lipid phase is L alpha, there is little or no fusion, i.e., mixing of aqueous contents, or leakage. However, as the temperature reaches delta TI, there is a rapid increase in both fusion and leakage rates. At temperatures above TH, the liposomes show aggregation-dependent lysis, as the rapid formation of HII phase precursors disrupts the membranes. We show that the correspondence between the fusion and leakage kinetics and the observed phase behavior is easily rationalized in terms of a recent kinetic theory of L alpha/inverted phase transitions. In particular, it is likely that membrane fusion and the L alpha/inverted cubic phase transition proceed via a common set of intermembrane intermediates

  7. The impact transconductance parameter and threshold voltage of MOSFET’s in static characteristics of CMOS inverter

    Directory of Open Access Journals (Sweden)

    Milaim Zabeli

    2017-11-01

    Full Text Available The objective of this paper is to research the impact of electrical and physical parameters that characterize the complementary MOSFET transistors (NMOS and PMOS transistors in the CMOS inverter for static mode of operation. In addition to this, the paper also aims at exploring the directives that are to be followed during the design phase of the CMOS inverters that enable designers to design the CMOS inverters with the best possible performance, depending on operation conditions. The CMOS inverter designed with the best possible features also enables the designing of the CMOS logic circuits with the best possible performance, according to the operation conditions and designers’ requirements.

  8. 21 CFR 184.1859 - Invert sugar.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an aqueous...

  9. Comparative Study of Modulation Techniques for Two-Level Voltage Source Inverters

    Directory of Open Access Journals (Sweden)

    Barry W. Williams

    2016-06-01

    Full Text Available A detailed comparative study of modulation techniques for single and three phase dc-ac inverters is presented.  Sinusoidal Pulse Width Modulation, Triplen Sinusoidal Pulse Width Modulation, Space Vector Modulation, Selective Harmonic Elimination and Wavelet Modulation are assessed and compared in terms of maximum fundamental output, harmonic performance, switching losses and operational mode.  The presented modulation techniques are applied to single and three phase voltage source inverters and are simulated using SIMULINK.  The simulation results clarify the inverter performance achieved using the different modulations techniques.

  10. Shunt Active-Power-Filter Topology Based on Parallel Interleaved Inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Asiminoaei, Lucian; Aeloiza, E.

    2008-01-01

    In this paper, an interleaved active-power-filter concept with reduced size of passive components is discussed. The topology is composed of two pulsewidth-modulation interleaved voltage-source inverters connected together on the ac line and sharing the same dc-link capacitor. The advantages......, because the power sharing allows one to use a higher switching frequency in each inverter. This paper analyzes the design of the passive components and gives a practical and low-cost solution for the minimization of the circulation currents between the inverters, by using common-mode coils. Several...

  11. NREL Evaluates Advanced Solar Inverter Performance for Hawaiian Electric

    Science.gov (United States)

    Companies | Energy Systems Integration Facility | NREL NREL Evaluates Advanced Solar Inverter Performance for Hawaiian Electric Companies NREL Evaluates Advanced Solar Inverter Performance for Hawaiian performance and impacts of today's advanced solar inverters, as well as proprietary feedback to the inverter

  12. Contrast Dose and Radiation Dose Reduction in Abdominal Enhanced Computerized Tomography Scans with Single-phase Dual-energy Spectral Computerized Tomography Mode for Children with Solid Tumors

    OpenAIRE

    Tong Yu; Jun Gao; Zhi-Min Liu; Qi-Feng Zhang; Yong Liu; Ling Jiang; Yun Peng

    2017-01-01

    Background: Contrast dose and radiation dose reduction in computerized tomography (CT) scan for adult has been explored successfully, but there have been few studies on the application of low-concentration contrast in pediatric abdominal CT examinations. This was a feasibility study on the use of dual-energy spectral imaging and adaptive statistical iterative reconstruction (ASiR) for the reduction of radiation dose and iodine contrast dose in pediatric abdominal CT patients with solid tumors...

  13. A New Green Power Inverter for Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Gert Karmisholt; Klumpner, Christian; Kjær, Søren Bækhøj

    2002-01-01

    This paper presents a new grid connected inverter for fuel cells. It consists of a two stage power conversion topology. Since the fuel cell operates with a low voltage in a wide voltage range (25 V-45 V) this volt- age must be transformed to around 350-400 V in order to invert this dc power into ac...... power to the grid. The proposed converter consists of an isolated dc-dc converter cascaded with a single phase H-bridge inverter. The dc-dc converter is a current-fed push-pull converter. A new dedicated voltage mode startup procedure has been developed in order to limit the inrush current during...... startup. The inverter is controlled as a power factor controller with resistor emulation.Experimental results of converter efficiency, grid performance and fuel cell response are shown for a 1 kW prototype. The proposed converter exhibits a high efficiency in a wide power range (higher than 92...

  14. Fault-tolerant three-level inverter

    Science.gov (United States)

    Edwards, John; Xu, Longya; Bhargava, Brij B.

    2006-12-05

    A method for driving a neutral point clamped three-level inverter is provided. In one exemplary embodiment, DC current is received at a neutral point-clamped three-level inverter. The inverter has a plurality of nodes including first, second and third output nodes. The inverter also has a plurality of switches. Faults are checked for in the inverter and predetermined switches are automatically activated responsive to a detected fault such that three-phase electrical power is provided at the output nodes.

  15. Effective switching frequency multiplier inverter

    Science.gov (United States)

    Su, Gui-Jia [Oak Ridge, TN; Peng, Fang Z [Okemos, MI

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  16. Indoor Autonomous Control of a Two-Wheeled Inverted Pendulum Vehicle Using Ultra Wide Band Technology.

    Science.gov (United States)

    Xia, Dunzhu; Yao, Yanhong; Cheng, Limei

    2017-06-15

    In this paper, we aimed to achieve the indoor tracking control of a two-wheeled inverted pendulum (TWIP) vehicle. The attitude data are acquired from a low cost micro inertial measurement unit (IMU), and the ultra-wideband (UWB) technology is utilized to obtain an accurate estimation of the TWIP's position. We propose a dual-loop control method to realize the simultaneous balance and trajectory tracking control for the TWIP vehicle. A robust adaptive second-order sliding mode control (2-RASMC) method based on an improved super-twisting (STW) algorithm is investigated to obtain the control laws, followed by several simulations to verify its robustness. The outer loop controller is designed using the idea of backstepping. Moreover, three typical trajectories, including a circle, a trifolium and a hexagon, have been designed to prove the adaptability of the control combinations. Six different combinations of inner and outer loop control algorithms have been compared, and the characteristics of inner and outer loop algorithm combinations have been analyzed. Simulation results demonstrate its tracking performance and thus verify the validity of the proposed control methods. Trajectory tracking experiments in a real indoor environment have been performed using our experimental vehicle to further validate the feasibility of the proposed algorithm in practice.

  17. Inverted annular flow experimental study

    International Nuclear Information System (INIS)

    De Jarlais, G.; Ishii, M.

    1985-04-01

    Steady-state inverted annular flow of Freon 113 in up flow was established in a transparent test section. Using a special inlet configuration consisting of long aspect-ratio liquid nozzles coaxially centered within a heated quartz tube, idealized inverted annular flow initial geometry (cylindrical liquid core surrounded by coaxial annulus of gas) could be established. Inlet liquid and gas flowrates, liquid subcooling, and gas density (using various gas species) were measured and varied systematically. The hydrodynamic behavior of the liquid core, and the subsequent downstream break-up of this core into slugs, ligaments and/or droplets of various sizes, was observed. In general, for low inlet liquid velocities it was observed that after the initial formation of roll waves on the liquid core surface, an agitated region of high surface area, with attendant high momentum and energy transfers, occurs. This agitated region appears to propagate downsteam in a quasi-periodic pattern. Increased inlet liquid flow rates, and high gas annulus flow rates tend to diminish the significance of this agitated region. Observed inverted annular flow (and subsequent downstream flow pattern) hydrodynamic behavior is reported, and comparisons are drawn to data generated by previous experimenters studying post-CHF flow

  18. Characteristics of MAO coating obtained on ZK60 Mg alloy under two and three steps voltage-increasing modes in dual electrolyte

    Science.gov (United States)

    Yang, Jun; Wang, Ze-Xin; Lu, Sheng; Lv, Wei-gang; Jiang, Xi-zhi; Sun, Lei

    2017-03-01

    The micro-arc oxidation process was conducted on ZK60 Mg alloy under two and three steps voltage-increasing modes by DC pulse electrical source. The effect of each mode on current-time responses during MAO process and the coating characteristic were analysed and discussed systematically. The microstructure, thickness and corrosion resistance of MAO coatings were evaluated by scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), microscope with super-depth of field and electrochemical impedance spectroscopy (EIS). The results indicate that two and three steps voltage-increasing modes can improve weak spark discharges with insufficient breakdown strength in later period during the MAO process. Due to higher value of voltage and voltage increment, the coating with maximum thickness of about 20.20μm formed under two steps voltage-increasing mode shows the best corrosion resistance. In addition, the coating fabricated under three steps voltage-increasing mode shows a smoother coating with better corrosion resistance due to the lower amplitude of voltage-increasing.

  19. A comparison of co-current and counter-current modes of operation for a novel hydrogen-permselective membrane dual-type FTS reactor in GTL technology

    Energy Technology Data Exchange (ETDEWEB)

    Rahimpour, M.R.; Forghani, A.A.; Mostafazadeh, A. Khosravanipour; Shariati, A. [Chemical Engineering Department, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz 71345 (Iran)

    2010-01-15

    In this work, a comparison of co-current and counter-current modes of operation for a novel hydrogen-permselective membrane reactor for Fischer-Tropsch Synthesis (FTS) has been carried out. In both modes of operations, a system with two-catalyst bed instead of one single catalyst bed is developed for FTS reactions. In the first catalytic reactor, the synthesis gas is partly converted to products in a conventional water-cooled fixed-bed reactor, while in the second reactor which is a membrane fixed-bed reactor, the FTS reactions are completed and heat of reaction is used to preheat the feed synthesis gas to the first reactor. In the co-current mode, feed gas is entered into the tubes of the second reactor in the same direction with the reacting gas stream in shell side while in the counter-current mode the gas streams are in the opposite direction. Simulation results for both co-current and counter-current modes have been compared in terms of temperature, gasoline and CO{sub 2} yields, H{sub 2} and CO conversion, selectivity of components as well as permeation rate of hydrogen through the membrane. The results showed that the reactor in the co-current configuration operates with lower conversion and lower permeation rate of hydrogen, but it has more favorable profile of temperature. The counter-current mode of operation decreases undesired products such as CO{sub 2} and CH{sub 4} and also produces more gasoline. (author)

  20. Ultra-low-loss inverted taper coupler for silicon-on-insulator ridge waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    An ultra-low-loss coupler for interfacing a silicon-on-insulator ridge waveguide and a single-mode fiber in both polarizations is presented. The inverted taper coupler, embedded in a polymer waveguide, is optimized for both the transverse-magnetic and transverse-electric modes through tapering...... the width of the silicon-on-insulator waveguide from 450 nm down to less than 15 nm applying a thermal oxidation process. Two inverted taper couplers are integrated with a 3-mm long silicon-on-insulator ridge waveguide in the fabricated sample. The measured coupling losses of the inverted taper coupler...... for transverse-magnetic and transverse-electric modes are ~0.36 dB and ~0.66 dB per connection, respectively....

  1. A variable-mode stator consequent pole memory machine

    Science.gov (United States)

    Yang, Hui; Lyu, Shukang; Lin, Heyun; Zhu, Z. Q.

    2018-05-01

    In this paper, a variable-mode concept is proposed for the speed range extension of a stator-consequent-pole memory machine (SCPMM). An integrated permanent magnet (PM) and electrically excited control scheme is utilized to simplify the flux-weakening control instead of relatively complicated continuous PM magnetization control. Due to the nature of memory machine, the magnetization state of low coercive force (LCF) magnets can be easily changed by applying either a positive or negative current pulse. Therefore, the number of PM poles may be changed to satisfy the specific performance requirement under different speed ranges, i.e. the machine with all PM poles can offer high torque output while that with half PM poles provides wide constant power range. In addition, the SCPMM with non-magnetized PMs can be considered as a dual-three phase electrically excited reluctance machine, which can be fed by an open-winding based dual inverters that provide direct current (DC) bias excitation to further extend the speed range. The effectiveness of the proposed variable-mode operation for extending its operating region and improving the system reliability is verified by both finite element analysis (FEA) and experiments.

  2. Dual THz comb spectroscopy

    Science.gov (United States)

    Yasui, Takeshi

    2017-08-01

    Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10-7 in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

  3. Dual mode NIR long persistent phosphorescence and NIR-to-NIR Stokes luminescence in La{sub 3}Ga{sub 5}GeO{sub 14}: Cr{sup 3+}, Nd{sup 3+} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yiling; Li, Yang, E-mail: msliyang@scut.edu.cn; Qin, Xixi; Chen, Ruchun; Wu, Dakun; Liu, Shijian; Qiu, Jianrong, E-mail: qjr@scut.edu.cn

    2015-11-15

    Recently, long persistent phosphors (LPPs) have been considered to be the most prominent candidates for biomedical applications. However, the LPPs suffer from a dramatic decrease in luminescence intensity after incorporation into the tissue. Therefore, it is very necessary to develop the more competitive LPPs and acquire the reproducible tissue imaging. Here, we propose and experimentally demonstrate an effective bifunctional La{sub 3}Ga{sub 5}GeO{sub 14}: Cr{sup 3+}, Nd{sup 3+} phosphor with the interesting characteristic of near-infrared long persistent phosphorescence and NIR-to-NIR Stokes luminescence. Cr{sup 3+} and Nd{sup 3+} ions are simultaneously selected as the emission centers in order to take advantage of the remarkable phosphorescence properties of Cr{sup 3+}, and the appropriate energy level characteristic of NIR-excitation band (808 nm) and NIR-emission (1064 nm), and the ability as the brilliant auxiliary to create more efficient defects of Nd{sup 3+}. The efficient dual-modal emission is, accordingly utilized to realize the convenient, high-resolution global detection and local imaging. - Highlights: • Dual mode phosphor with NIR long afterglow and NIR-to-NIR Stokes luminescence. • Increasing the persistent duration due to the codoping of Nd. • Avoiding the noteworthy overheating effect due to the strong absorption at 980 nm.

  4. Sedimentary mode and reservoir genesis of dual grain banks at the Lower Cambrian Longwangmiao Fm carbonate ramp in the Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Jinhu Du

    2016-11-01

    Full Text Available The gas reservoir of the Lower Cambrian Longwangmiao Fm in the Sichuan Basin is a supergiant integral marine carbonate gas reservoir whose single scale is currently the largest in China. In order to figure out its sedimentary model and reservoir genesis, its geological structures and sedimentary settings and facies were analyzed comprehensively and the lithofacies paleographic map was plotted. It is revealed that the following sedimentary facies are successively developed in the Longwangmiao Fm from West Sichuan to Southeast Chongqing: diamictic tidal flat at the back ramp, grain bank (the upper bank at the inner/shallow ramp – interbank sea (depression, deeper open bay at the platform depression of inner ramp → evaporative lagoon → evaporative tidal flat, tempestite at the middle ramp – barrier beach – mud mound beach (the lower bank, and outer ramp – basin. Accordingly, the specific sedimentary model of dual grain banks in the Longwangmiao Fm carbonate ramp was established as follows. Firstly, in this model, dual grain banks are symmetrically developed with Wanzhou–Yibin platform depression as the axis, on whose dual sides the paleohighs have shallow water bodies with strong energy. Compared with the classical model, the new one has a new upper bank which is developed around the paleohighs covering an area of about 8 × 104 km2. Secondly, the upper bank is large for its paleogeomorphology being located at the highest position with the strongest water energy during deposition. Therefore, it is prone to dolomitization and meteoric dissolution respectively during contemporaneous–penecontemporaneous hot-dry and hot-humid periods, and especially the Caledonian–Early Hercynian denudation wedge out tends to undergo post-supergene multiphase karstification. Therefore, quality reservoirs are more developed on scale. Thirdly, the intergranular pores and vermes moldic pores were dissolved and enlarged due to the multiphase

  5. Monolithically integrated enhancement/depletion-mode AlGaN/GaN HEMT D flip-flop using fluorine plasma treatment

    International Nuclear Information System (INIS)

    Xie Yuanbin; Quan Si; Ma Xiaohua; Zhang Jincheng; Li Qingmin; Hao Yue

    2011-01-01

    Depletion-mode and enhancement-mode AlGaN/GaN HEMTs using fluorine plasma treatment were integrated on one wafer. Direct-coupled FET logic circuits, such as an E/D HEMT inverter, NAND gate and D flip-flop, were fabricated on an AlGaN/GaN heterostructure. The D flip-flop and NAND gate are demonstrated in a GaN system for the first time. The dual-gate AlGaN/GaN E-HEMT substitutes two single-gate E-HEMTs for simplifying the NAND gate and shrinking the area, integrating with a conventional AlGaN/GaN D-HEMT and demonstrating a NAND gate. E/D-mode D flip-flop was fabricated by integrating the inverters and the NAND gate on the AlGaN/GaN heterostructure. At a supply voltage of 2 V, the E/D inverter shows an output logic swing of 1.7 V, a logic-low noise margin of 0.49 V and a logic-high noise margin of 0.83 V. The NAND gate and D flip-flop showed correct logic function demonstrating promising potential for GaN-based digital ICs. (semiconductor integrated circuits)

  6. Multilevel Inverter by Cascading Industrial VSI

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Blaabjerg, Frede; Pedersen, John Kim

    2002-01-01

    In this paper the modularity concept applied to medium-voltage adjustable speed drives is addressed. First, the single-phase cascaded voltage-source inverter that uses series connection of IGBT H-bridge modules with isolated dc-buses is presented. Next, a novel three-phase cascaded voltage......-source inverter that uses three IGBT triphase inverter modules along with an output transformer to obtain a 3 p.u. multilevel output voltage is introduced. The system yields in high-quality multistep voltage with up to 4 levels and low dv/dt, balanced operation of the inverter modules, each supplying a third...... of the motor rated kVA. The concept of using cascaded inverters is further extended to a new modular motor-modular inverter system where the motor winding connections are reconnected into several three-phase groups, either six-lead or 12-lead connection according to the voltage level, each powered...

  7. A comparative study on dual colour soft aperture cascaded second ...

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... second-order mode-locking with different nonlinear optical crystals ... delivers stable dual wavelength cw mode-locked pulse train with pulse ... Mode-locking; ultrafast processes; optical susceptibility; frequency conversion;.

  8. Determination of the binding mode for the cyclopentapeptide CXCR4 antagonist FC131 using a dual approach of ligand modifications and receptor mutagenesis

    DEFF Research Database (Denmark)

    Thiele, Stefanie; Mungalpara, J; Steen, A

    2014-01-01

    have previously been suggested based on molecular docking guided by structure-activity relationship (SAR) data; however, none of these have been verified by in vitro experiments. EXPERIMENTAL APPROACH: Heterologous (125) I-12G5-competition binding and functional assays (inhibition of CXCL12-mediated...... activation) of FC131 and three analogues were performed on wild-type CXCR4 and 25 receptor mutants. Computational modelling was used to rationalize the experimental data. KEY RESULTS: The Arg(2) and 2-Nal(3) side chains of FC131 interact with residues in TM-3 (His(113) , Asp(171) ) and TM-5 (hydrophobic......-bond in CXCR4 crystal structures and mutation of either residue to Ala abolishes CXCR4 activity. CONCLUSIONS AND IMPLICATIONS: Ligand modification, receptor mutagenesis and computational modelling approaches were used to identify the binding mode of FC131 in CXCR4, which was in agreement with binding modes...

  9. Multicenter, prospective, randomized safety and efficacy study of a new atrial-based managed ventricular pacing mode (MVP) in dual chamber ICDs.

    Science.gov (United States)

    Sweeney, Michael O; Ellenbogen, Kenneth A; Casavant, David; Betzold, Robert; Sheldon, Todd; Tang, Feng; Mueller, Megan; Lingle, John

    2005-08-01

    Ventricular desynchronization caused by right ventricular pacing may impair ventricular function and increase risk of heart failure (CHF), atrial fibrillation (AF), and death. Conventional DDD/R mode often results in high cumulative percentage ventricular pacing (Cum%VP). We hypothesized that a new managed ventricular pacing mode (MVP) would safely provide AAI/R pacing with ventricular monitoring and DDD/R during AV block (AVB) and reduce Cum%VP compared to DDD/R. MVP RAMware was downloaded in 181 patients with Marquis DR ICDs. Patients were initially randomized to either MVP or DDD/R for 1 month, then crossed over to the opposite mode for 1 month. ICD diagnostics were analyzed for cumulative percentage atrial pacing (Cum%AP), Cum%VP, and duration of DDD/R pacing for spontaneous AVB. Baseline characteristics included age 66 +/- 12 years, EF 36 +/- 14%, and NYHA Class II-III 36%. Baseline PR interval was 190 +/- 53 msec and programmed AV intervals (DDD/R) were 216 +/- 50 (paced)/189 +/- 53 (sensed) msec. Mean Cum%VP was significantly lower in MVP versus DDD/R (4.1 +/- 16.3 vs 73.8 +/- 32.5, P MVP were 85.0 and 99.9, respectively. Mean Cum%AP was not different between MVP versus DDD/R (48.7 +/- 38.5 vs 47.3 +/- 38.4, P = 0.83). During MVP overall time spent in AAI/R was 89.6% (intrinsic conduction), DDD/R 6.7% (intermittent AVB), and DDI/R 3.7% (AF). No adverse events were attributed to MVP. MVP safely achieves functional atrial pacing by limiting ventricular pacing to periods of intermittent AVB and AF in ICD patients, significantly reducing Cum%VP compared to DDD/R. MVP is a universal pacing mode that adapts to AVB and AF, providing both atrial pacing and ventricular pacing support when needed.

  10. Analysis and Modeling of Circulating Current in Two Parallel-Connected Inverters

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand

    2015-01-01

    Parallel-connected inverters are gaining attention for high power applications because of the limited power handling capability of the power modules. Moreover, the parallel-connected inverters may have low total harmonic distortion of the ac current if they are operated with the interleaved pulse...... this model, the circulating current between two parallel-connected inverters is analysed in this study. The peak and root mean square (rms) values of the normalised circulating current are calculated for different PWM methods, which makes this analysis a valuable tool to design a filter for the circulating......-width modulation (PWM). However, the interleaved PWM causes a circulating current between the inverters, which in turn causes additional losses. A model describing the dynamics of the circulating current is presented in this study which shows that the circulating current depends on the common-mode voltage. Using...

  11. A dual-mode hemispherical sparse array for 3D passive acoustic mapping and skull localization within a clinical MRI guided focused ultrasound device

    Science.gov (United States)

    Crake, Calum; Brinker, Spencer T.; Coviello, Christian M.; Livingstone, Margaret S.; McDannold, Nathan J.

    2018-03-01

    Previous work has demonstrated that passive acoustic imaging may be used alongside MRI for monitoring of focused ultrasound therapy. However, past implementations have generally made use of either linear arrays originally designed for diagnostic imaging or custom narrowband arrays specific to in-house therapeutic transducer designs, neither of which is fully compatible with clinical MR-guided focused ultrasound (MRgFUS) devices. Here we have designed an array which is suitable for use within an FDA-approved MR-guided transcranial focused ultrasound device, within the bore of a 3 Tesla clinical MRI scanner. The array is constructed from 5  ×  0.4 mm piezoceramic disc elements arranged in pseudorandom fashion on a low-profile laser-cut acrylic frame designed to fit between the therapeutic elements of a 230 kHz InSightec ExAblate 4000 transducer. By exploiting thickness and radial resonance modes of the piezo discs the array is capable of both B-mode imaging at 5 MHz for skull localization, as well as passive reception at the second harmonic of the therapy array for detection of cavitation and 3D passive acoustic imaging. In active mode, the array was able to perform B-mode imaging of a human skull, showing the outer skull surface with good qualitative agreement with MR imaging. Extension to 3D showed the array was able to locate the skull within  ±2 mm/2° of reference points derived from MRI, which could potentially allow registration of a patient to the therapy system without the expense of real-time MRI. In passive mode, the array was able to resolve a point source in 3D within a  ±10 mm region about each axis from the focus, detect cavitation (SNR ~ 12 dB) at burst lengths from 10 cycles to continuous wave, and produce 3D acoustic maps in a flow phantom. Finally, the array was used to detect and map cavitation associated with microbubble activity in the brain in nonhuman primates.

  12. High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

    Science.gov (United States)

    Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

    2017-08-01

    Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

  13. A PWM strategy for acoustic noise reduction for grid-connected single-phase inverters

    Energy Technology Data Exchange (ETDEWEB)

    Shao, R.; Guo, Z.; Chang, L. [New Brunswick Univ., Fredericton, NB (Canada). Dept. of Electrical and Computer Engineering

    2006-07-01

    This paper presented a newly proposed and improved pulse width modulation (PWM) strategy for grid-connected single-phase inverters. Small distributed generators using energy from renewable resources such as PV and wind systems typically use grid-connected single-phase inverters as voltage source inverters for good acoustic performance. PWM is generally applied in these inverters in order to achieve good waveforms of output current as required by interconnection standards. In routine simultaneous switching PWM methods, the current ripples through the inverter output filter inductor are at the carrier switching frequency, which is one of the major causes for inverter acoustic noise. The new PWM strategy effectively alleviates acoustic noise and improves output power quality. It is based on the principle of evenly splitting the switching of Insulated Gate Bipolar Transistors (IGBT) in each switching cycle among all IGBTs of the full bridge, thereby using a non-simultaneous mode of PWM which doubles the output current ripple frequency. This increases the inductor current ripple frequency to twice the carrier frequency. It is therefore possible to increase the current ripple frequency, or noise frequency into the range of ultrasonic which is inaudible to the human ear, without increasing the inverter's switching frequency to which the inverter's switching loss is proportional. In addition, this new PWM scheme can reduce the output current harmonics distortion and dc link current ripples. As such, lower capacitance in dc link capacitors and lower inductance of output inductor are needed. The improved PWM scheme was verified in a 3 kW grid-connected single-phase inverter. It was shown that the PWM strategy can be readily implemented with a digital signal processing microcontroller. 8 refs., 11 figs.

  14. Three-Phase Cascaded Multilevel Inverter Using Power Cells With Two Inverter Legs in Series

    NARCIS (Netherlands)

    Waltrich, G.; Barbi, I.

    2010-01-01

    In this paper, a modular three-phase multilevel inverter specially suited for electrical drive applications is proposed. Unlike the cascaded H-bridge inverter, this topology is based on power cells connected in cascade using two inverter legs in series. A detailed analysis of the structure and the

  15. Sliding Mode Control of Diesel Engine Air-path System With Dual-loop EGR and VGT Based on the Reduced-order Model

    Directory of Open Access Journals (Sweden)

    Kim Sooyoung

    2016-01-01

    Full Text Available This paper presents the design of a model-based controller for the diesel engine air-path system. The controller is implemented based on a reduced order model consisting of only pressure and power dynamics with practical concerns. To deal with the model uncertainties effectively, a sliding mode controller, which is robust to model uncertainties, is proposed for the air-path system. The control performance of the proposed control scheme is verified through simulation with the valid plant model of a 6,000cc heavy duty diesel engine.

  16. Stand-Alone Microgrid Inverter Controller Design for Nonlinear, Unbalanced Load with Output Transformer

    Directory of Open Access Journals (Sweden)

    Jae-Uk Lim

    2018-04-01

    Full Text Available This paper proposes a technique that compensates for unbalance and nonlinearity in microgrid inverters with power transformers operating in stand-alone mode. When a microgrid inverter is operating in stand-alone mode, providing high-quality power is very important. When an unbalanced, nonlinear load is connected, zero sequence current and negative sequence current occur, which leads to an unbalanced output voltage. This paper examines why the zero sequence component occurs differently depending on the structure of a three-phase transformer connected to the inverter output terminal, and it proposes a method for controlling the zero sequence component. It also uses a resonant controller to remove the harmonics that correspond to the negative sequence component and the nonlinear component. The proposed elements were verified by a Powersim (PSIM simulation.

  17. Power Control Flexibilities for Grid-Connected Multi-Functional Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Wang, Huai

    2016-01-01

    and intelligent services, such as fault ride-through and reactive power compensation, is the key to attain higher utilisation of solar PV energy. Such functionalities for the future PV inverters can contribute to reduced cost of energy, and thus enable more cost-effective PV installations. To implement...... the advanced features, a flexible power controller is developed in this study, which can be configured in the PV inverter and flexibly change from one to another mode during operation. Based on the single-phase PQ theory, the control strategy offers the possibilities to generate appropriate references...... for the inner current control loop. The references depend on system conditions and also specific demands from both system operators and prosumers. Besides, this power control strategy can be implemented in commercial PV inverters as a standardised function, and also the operation modes can be achieved online...

  18. Selection of DC voltage magnitude using Fibonacci series for new hybrid asymmetrical multilevel inverter with minimum PIV

    Directory of Open Access Journals (Sweden)

    M.R. Banaei

    2014-09-01

    Full Text Available Multilevel inverters are suggested to obtain high quality output voltage. In this paper, a new hybrid configuration is proposed, obtained by cascading one four switches H-bridge cell with a family of multilevel inverters. In addition, by the use of specific sequence for value of DC sources named Fibonacci series, asymmetrical topology of proposed inverter is introduced. Main advantages are that proposed inverter has least Peak Inverse Voltage (PIV than other conventional multilevel converters in both symmetric and asymmetric modes. Also, this topology doubles the number of output levels using only one cascaded four switches H-bridge cell. The PCI-1716 DAQ using PC has been used to generate switching pulses in experimental results. For presenting valid performance of proposed configuration, simulation results carried out by MATLAB/SIMULINK software and the validity of the proposed multilevel inverter is verified by experimental results.

  19. Invert Effective Thermal Conductivity Calculation

    International Nuclear Information System (INIS)

    M.J. Anderson; H.M. Wade; T.L. Mitchell

    2000-01-01

    The objective of this calculation is to evaluate the temperature-dependent effective thermal conductivities of a repository-emplaced invert steel set and surrounding ballast material. The scope of this calculation analyzes a ballast-material thermal conductivity range of 0.10 to 0.70 W/m · K, a transverse beam spacing range of 0.75 to 1.50 meters, and beam compositions of A 516 carbon steel and plain carbon steel. Results from this calculation are intended to support calculations that identify waste package and repository thermal characteristics for Site Recommendation (SR). This calculation was developed by Waste Package Department (WPD) under Office of Civilian Radioactive Waste Management (OCRWM) procedure AP-3.12Q, Revision 1, ICN 0, Calculations

  20. Inverted base pavements: construction and performance

    KAUST Repository

    Papadopoulos, Efthymios

    2017-05-11

    Inverted base pavements involve a well-compacted granular aggregate base built between a thin asphalt concrete layer and a cement-treated base. Inverted base pavements can be constructed using conventional equipment and procedures but require proper quality control. This study reviews the extensive South African experience and case histories in the USA. Accumulating evidence suggests that inverted base pavements are a viable alternative and can outperform conventional pavements at a lower cost. Inverted base pavements rely on the complementary interaction between layers. The cement-treated base provides a stiff foundation for efficient compaction and constrains the deformation of the stress-sensitive granular aggregate base. The thin asphalt surface layer deforms as a membrane and develops low tensile stress. Additional large-scale field tests should be conducted to assess the performance of inverted base pavement designs in a wide range of conditions relevant to the USA.

  1. On Invertible Sampling and Adaptive Security

    DEFF Research Database (Denmark)

    Ishai, Yuval; Kumarasubramanian, Abishek; Orlandi, Claudio

    2011-01-01

    functionalities was left open. We provide the first convincing evidence that the answer to this question is negative, namely that some (randomized) functionalities cannot be realized with adaptive security. We obtain this result by studying the following related invertible sampling problem: given an efficient...... sampling algorithm A, obtain another sampling algorithm B such that the output of B is computationally indistinguishable from the output of A, but B can be efficiently inverted (even if A cannot). This invertible sampling problem is independently motivated by other cryptographic applications. We show......, under strong but well studied assumptions, that there exist efficient sampling algorithms A for which invertible sampling as above is impossible. At the same time, we show that a general feasibility result for adaptively secure MPC implies that invertible sampling is possible for every A, thereby...

  2. Elimination of zero sequence circulating current between parallel operating three-level inverters

    DEFF Research Database (Denmark)

    Li, Kai; Wang, Xiaodong; Dong, Zhenhua

    2016-01-01

    In order to suppress the zero sequence circulating currents (ZSCCs) between parallel operating three level voltage source inverters with common AC and DC buses, a common mode voltage reduction PWM (CMVR-PWM) technique and neural point potentials (NPPs) control based method is proposed in this paper...

  3. Harmonic Instability Assessment Using State-Space Modeling and Participation Analysis in Inverter-Fed Power Systems

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    parameters on the harmonic instability of the power system. Moreover, the harmonic-frequency oscillation modes are identified, where participation analysis is presented to evaluate the contributions of different states to these modes and to further reveal how the system gives rise to harmonic instability......This paper presents a harmonic instability analysis method using state-space modeling and participation analysis in the inverter-fed ac power systems. A full-order state-space model for the droop-controlled Distributed Generation (DG) inverter is built first, including the time delay of the digital...... control system, inner current and voltage control loops, and outer droop-based power control loop. Based on the DG inverter model, an overall state-space model of a two-inverter-fed system is established. The eigenvalue-based stability analysis is then presented to assess the influence of controller...

  4. Pre-inverted SESAME data table construction enhancements to correct unexpected inverse interpolation pathologies in EOSPAC 6

    Energy Technology Data Exchange (ETDEWEB)

    Pimentel, David A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sheppard, Daniel G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-02-01

    It was recently demonstrated that EOSPAC 6 continued to incorrectly create and interpolate pre-inverted SESAME data tables after the release of version 6.3.2beta.2. Significant interpolation pathologies were discovered to occur when EOSPAC 6's host software enabled pre-inversion with the EOS_INVERT_AT_SETUP option. This document describes a solution that uses data transformations found in EOSPAC 5 and its predecessors. The numerical results and performance characteristics of both the default and pre-inverted interpolation modes in both EOSPAC 6.3.2beta.2 and the fixed logic of EOSPAC 6.4.0beta.1 are presented herein, and the latter software release is shown to produce significantly-improved numerical results for the pre-inverted interpolation mode.

  5. Control of Grid Connected Photovoltaic System Using Three-Level T-Type Inverter

    Science.gov (United States)

    Zorig, Abdelmalik; Belkeiri, Mohammed; Barkat, Said; Rabhi, Abdelhamid

    2016-08-01

    Three-level T-Type inverter (3LT2I) topology has numerous advantageous compared to three-level neutral-point-clamped (NPC) inverter. The main benefits of 3LT2I inverter are the efficiency, inverter cost, switching losses, and the quality of output voltage waveforms. In this paper, a photovoltaic distributed generation system based on dual-stage topology of DC-DC boost converter and 3LT2I is introduced. To that end, a decoupling control strategy of 3LT2I is proposed to control the current injected into the grid, reactive power compensation, and DC-link voltage. The resulting system is able to extract the maximum power from photovoltaic generator, to achieve sinusoidal grid currents, and to ensure reactive power compensation. The voltage-balancing control of two split DC capacitors of the 3LT2I is achieved using three-level space vector modulation with balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors. The proposed system performance is investigated at different operating conditions.

  6. Inverter Output Filter Effect on PWM Motor Drives of a Flywheel Energy Storage System

    Science.gov (United States)

    Santiago, Walter

    2004-01-01

    NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheel systems for small satellite energy storage and attitude control applications. One research and development area has been the minimization of the switching noise produced by the pulsed width modulated (PWM) inverter that drives the flywheel permanent magnet motor/generator (PM M/G). This noise can interfere with the flywheel M/G hardware and the system avionics hampering the full speed performance of the flywheel system. One way to attenuate the inverter switching noise is by placing an AC filter at the three phase output terminals of the inverter with the filter neutral point connected to the DC link (DC bus) midpoint capacitors. The main benefit of using an AC filter in this fashion is the significant reduction of the inverter s high dv/dt switching and its harmonics components. Additionally, common mode (CM) and differential mode (DM) voltages caused by the inverter s high dv/dt switching are also reduced. Several topologies of AC filters have been implemented and compared. One AC filter topology consists of a two-stage R-L-C low pass filter. The other topology consists of the same two-stage R-L-C low pass filter with a series connected trap filter (an inductor and capacitor connected in parallel). This paper presents the analysis, design and experimental results of these AC filter topologies and the comparison between the no filter case and conventional AC filter.

  7. A Lithium/Polysulfide Battery with Dual-Working Mode Enabled by Liquid Fuel and Acrylate-Based Gel Polymer Electrolyte.

    Science.gov (United States)

    Liu, Ming; Ren, Yuxun; Zhou, Dong; Jiang, Haoran; Kang, Feiyu; Zhao, Tianshou

    2017-01-25

    The low density associated with low sulfur areal loading in the solid-state sulfur cathode of current Li-S batteries is an issue hindering the development of this type of battery. Polysulfide catholyte as a recyclable liquid fuel was proven to enhance both the energy density and power density of the battery. However, a critical barrier with this lithium (Li)/polysulfide battery is that the shuttle effect, which is the crossover of polysulfides and side deposition on the Li anode, becomes much more severe than that in conventional Li-S batteries with a solid-state sulfur cathode. In this work, we successfully applied an acrylate-based gel polymer electrolyte (GPE) to the Li/polysulfide system. The GPE layer can effectively block the detrimental diffusion of polysulfides and protect the Li metal from the side passivation reaction. Cathode-static batteries utilizing 2 M catholyte (areal sulfur loading of 6.4 mg cm -2 ) present superior cycling stability (727.4 mAh g -1 after 500 cycles at 0.2 C) and high rate capability (814 mAh g -1 at 2 C) and power density (∼10 mW cm -2 ), which also possess replaceable and encapsulated merits for mobile devices. In the cathode-flow mode, the Li/polysulfide system with catholyte supplied from an external tank demonstrates further improved power density (∼69 mW cm -2 ) and stable cycling performance. This novel and simple Li/polysulfide system represents a significant advancement of high energy density sulfur-based batteries for future power sources.

  8. Leakage current measurement in transformerless PV inverters

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Sera, Dezso; Mathe, Laszlo

    2012-01-01

    Photovoltaic (PV) installations have seen a huge increase during the last couple of years. Transformerless PV inverters are gaining more share of the total inverter market, due to their high conversion efficiency, small weight and size. Nevertheless safety should have an important role in case...... of these tranformerless systems, due to the missing galvanic isolation. Leakage and fault current measurement is a key issue for these inverter topologies to be able to comply with the required safety standards. This article presents the test results of two different current measurement sensors that were suggested...

  9. Switching Characteristics of Ferroelectric Transistor Inverters

    Science.gov (United States)

    Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.

    2010-01-01

    This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

  10. Static Characteristics of the Ferroelectric Transistor Inverter

    Science.gov (United States)

    Mitchell, Cody; Laws, crystal; MacLeond, Todd C.; Ho, Fat D.

    2010-01-01

    The inverter is one of the most fundamental building blocks of digital logic, and it can be used as the foundation for understanding more complex logic gates and circuits. This paper presents the characteristics of an inverter circuit using a ferroelectric field-effect transistor. The voltage transfer characteristics are analyzed with respect to varying parameters such as supply voltage, input voltage, and load resistance. The effects of the ferroelectric layer between the gate and semiconductor are examined, and comparisons are made between the inverters using ferroelectric transistors and those using traditional MOSFETs.

  11. A Wearable Goggle Navigation System for Dual-Mode Optical and Ultrasound Localization of Suspicious Lesions: Validation Studies Using Tissue-Simulating Phantoms and an Ex Vivo Human Breast Tissue Model.

    Directory of Open Access Journals (Sweden)

    Zeshu Zhang

    Full Text Available Surgical resection remains the primary curative treatment for many early-stage cancers, including breast cancer. The development of intraoperative guidance systems for identifying all sites of disease and improving the likelihood of complete surgical resection is an area of active ongoing research, as this can lead to a decrease in the need of subsequent additional surgical procedures. We develop a wearable goggle navigation system for dual-mode optical and ultrasound imaging of suspicious lesions. The system consists of a light source module, a monochromatic CCD camera, an ultrasound system, a Google Glass, and a host computer. It is tested in tissue-simulating phantoms and an ex vivo human breast tissue model. Our experiments demonstrate that the surgical navigation system provides useful guidance for localization and core needle biopsy of simulated tumor within the tissue-simulating phantom, as well as a core needle biopsy and subsequent excision of Indocyanine Green (ICG-fluorescing sentinel lymph nodes. Our experiments support the contention that this wearable goggle navigation system can be potentially very useful and fully integrated by the surgeon for optimizing many aspects of oncologic surgery. Further engineering optimization and additional in vivo clinical validation work is necessary before such a surgical navigation system can be fully realized in the everyday clinical setting.

  12. Inverted CERN School of Computing

    CERN Multimedia

    IT Department

    2011-01-01

      The 5th edition of the Inverted CERN School of Computing (iCSC, “Where students turn into teachers”) will take place next Thursday and Friday (3 and 4 of March) at CERN, Building 31 - IT Amphitheatre - Third Floor. Attendance is free and open to everyone. The programme is designed so that you can attend the lectures that interest you. This year highlights: Cloud Computing, Software Engineering, Cryptography Registration is not mandatory, but will allow you to obtain a copy of the full booklet (first registered, first served). Programme overview: Thursday 3 March 2011 10:00 - 10:15 Introduction School opening 10:15 - 11:10 Lecture 1 Virtualization: what it is, how it works – Luigi Gallerani 11:20 - 12:15 Lecture 2 Server Virtualization at work – Carlos Garcia Fernandez 14:00 - 14:55 Lecture 3 Unweaving Clouds: Principles and Practice – Belmiro Moreira 15:30 - 16:25 Lecture 4 Understanding Cryptography: From Caesar to Public-Key – Nicola...

  13. Optimal Control of Micro Grid Operation Mode Seamless Switching Based on Radau Allocation Method

    Science.gov (United States)

    Chen, Xiaomin; Wang, Gang

    2017-05-01

    The seamless switching process of micro grid operation mode directly affects the safety and stability of its operation. According to the switching process from island mode to grid-connected mode of micro grid, we establish a dynamic optimization model based on two grid-connected inverters. We use Radau allocation method to discretize the model, and use Newton iteration method to obtain the optimal solution. Finally, we implement the optimization mode in MATLAB and get the optimal control trajectory of the inverters.

  14. Dual Regression

    OpenAIRE

    Spady, Richard; Stouli, Sami

    2012-01-01

    We propose dual regression as an alternative to the quantile regression process for the global estimation of conditional distribution functions under minimal assumptions. Dual regression provides all the interpretational power of the quantile regression process while avoiding the need for repairing the intersecting conditional quantile surfaces that quantile regression often produces in practice. Our approach introduces a mathematical programming characterization of conditional distribution f...

  15. Development of inverter for elevator door control

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.K.; Choi, U.D.; Jung, M.K.; Choi, S.K. [HHI R and D Center (Korea, Republic of); Yun, J.H.; Han, S.B. [HELCO R and D Center (Korea, Republic of)

    1995-07-01

    Most of the elevator door controllers have been controlled by DC Motors as an actuator. Recently, The control system using AC induction motor and general purpose inverter has been applied to control of elevator door. But there are some difficulties in making use of this system, such as adjustment of door speed pattern, door open-close time, and security of passenger safety. In order to solve these problems, a special inverter has been developed with an encoder feedback. From the result of field-test, we proved that a special inverter with encoder feedback device has come to considerable effect. Until now about 1,200 sets of these inverters are operated in Korea and about 100 sets are operated in South-east Asia. (author). 3 refs., 10 figs., 3 tabs.

  16. Inverted base pavements: construction and performance

    KAUST Repository

    Papadopoulos, Efthymios; Santamarina, Carlos

    2017-01-01

    quality control. This study reviews the extensive South African experience and case histories in the USA. Accumulating evidence suggests that inverted base pavements are a viable alternative and can outperform conventional pavements at a lower cost

  17. Performance analysis of new type grid-tied inverter-Aalborg Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Wang, Zhen; Ji, Junhao

    2014-01-01

    Aalborg Inverter is a grid-tied DC/AC inverter. In order to optimize the design, its power losses are analyzed in detail, combined with a description of the single-phase operating principle and the modulation strategy. A 2 kW / 220 V experimental prototype is constructed to verify the theoretical...... analysis. It is concluded that a minimize inductance in the power loop does help the inverter to achieve the high efficiency with the good dynamic performance....

  18. Work Station For Inverting Solar Cells

    Science.gov (United States)

    Feder, H.; Frasch, W.

    1982-01-01

    Final work station along walking-beam conveyor of solar-array assembly line turns each pretabbed solar cell over, depositing it back-side-up onto landing pad, which centers cell without engaging collector surface. Solar cell arrives at inverting work station collector-side-up with two interconnect tabs attached to collector side. Cells are inverted so that second soldering operation takes place in plain view of operator. Inversion protects collector from damage when handled at later stages of assembly.

  19. The CMOS Integration of a Power Inverter

    OpenAIRE

    Mannarino, Eric Francis

    2016-01-01

    Due to their falling costs, the use of renewable energy systems is expanding around the world. These systems require the conversion of DC power into grid-synchronous AC power. Currently, the inverters that carry out this task are built using discrete transistors. TowerJazz Semiconductor Corp. has created a commercial CMOS process that allows for blocking voltages of up to 700 V, effectively removing the barrier to integrating power inverters onto a single chip. This thesis explores this proce...

  20. Automatic load sharing in inverter modules

    Science.gov (United States)

    Nagano, S.

    1979-01-01

    Active feedback loads transistor equally with little power loss. Circuit is suitable for balancing modular inverters in spacecraft, computer power supplies, solar-electric power generators, and electric vehicles. Current-balancing circuit senses differences between collector current for power transistor and average value of load currents for all power transistors. Principle is effective not only in fixed duty-cycle inverters but also in converters operating at variable duty cycles.

  1. Base drive for paralleled inverter systems

    Science.gov (United States)

    Nagano, S. (Inventor)

    1980-01-01

    In a paralleled inverter system, a positive feedback current derived from the total current from all of the modules of the inverter system is applied to the base drive of each of the power transistors of all modules, thereby to provide all modules protection against open or short circuit faults occurring in any of the modules, and force equal current sharing among the modules during turn on of the power transistors.

  2. Improved Layout of Inverter for EMC Analysis

    OpenAIRE

    Yade , Ousseynou; Martin , Christian; Vollaire , Christian; Bréard , Arnaud; Ali , Marwan; Meuret , Régis; Hervé , Morel

    2017-01-01

    International audience; This paper details EMC (electromagnetic compatibility) analysis on an inverter application. The work deals with the whole power chain (±270Vdc input voltage to 3-phase 115 Vac output voltage). This inverter is composed by modular parts (power module and EMC filters) that supply motors in more electrical aircraft. Through our analysis an approach is defined to design a detailed lumped circuit model of the power module layout by using Q3D extractor and SABER software. Fr...

  3. Evaluación energética de un sistema de generación de 400 kWe en modo diesel‐gas licuado de petróleo//Energy analysis of a 400 kWe power system operated on dual fuel mode with diesel‐liquefied petroleum gas

    Directory of Open Access Journals (Sweden)

    Carlos‐A. Forero-Núñez

    2014-08-01

    Full Text Available El constante aumento en los precios de los combustibles impulsó el desarrollo de sistemas energéticos cada vez más eficientes y flexibles, los cuales permitan el uso de distintos tipos de combustibles, tales como el gas licuado de petróleo (GLP. El presente trabajo buscó analizar el comportamiento energético y ambiental que tiene una planta de generación de 400 kWe operada en modo diesel y dual diesel-GLP de pozo. La eficiencia energética total del sistema en el punto de máxima carga fue igual a 39,9 % en modo diesel y 35,1 % con una relación de sustitución del 28,5 % en modo dual. La adición de GLP resultó en una disminución del índice de emisiones de CO2 de 0,76 a 0,71 kgkWh-1. El adecuado comportamiento del sistema genera interesantes oportunidades para la disminución del impacto ambiental causado por los sistemas diesel, la diversificación de la canasta energética y la reducción de costos de generación eléctrica en pozos petroleros.Palabras claves: eficiencia energética, diesel, GLP, modo dual.________________________________________________________________________________AbstractThe continuous increase of the fuel costs promoted the development of more efficient and flexible power systems, which could use alternative fuels such as liquefied petroleum gas (LPG. This work aimed to analyze the performance and environmental effect of a 400kWe power system fed with diesel and diesel-LGP on a dual fuel mode. The total electric efficiency of this system at his maximum load was 39,9 % with diesel and 35,1 % at a 28,5 % substitution level on a dual fuel mode. The addition of LPG decreased the CO2 emission index from 0,76 to 0,71 kgkWh-1. The proper behavior of this system on a dual fuel mode mitigated the environmental impact of diesel internal combustion engines, diversified the energy market, and reduced the power generation costs onto petroleum extraction wells.Key words: energy efficiency, diesel, LPG, dual fuel mode.

  4. On Stability of Voltage Source Inverters in Weak Grids

    DEFF Research Database (Denmark)

    Adib, Aswad; Mirafza, Behrooz; Wang, Xiongfei

    2018-01-01

    As the number of inverters increases in the power grid, the stability of grid-tied inverters becomes an important concern for the power industry. In particular, a weak grid can lead to voltage fluctuations at the inverter terminals and consequently cause inverter instability. In this paper, impac...

  5. Hardness of deriving invertible sequences from finite state machines

    DEFF Research Database (Denmark)

    Hierons, Robert M.; Mousavi, Mohammad Reza; Thomsen, Michael Kirkedal

    2017-01-01

    invertible sequences; these allow one to construct additional UIOs once a UIO has been found. We consider three optimisation problems associated with invertible sequences: deciding whether there is a (proper) invertible sequence of length at least K; deciding whether there is a set of invertible sequences...

  6. Adaptive fuzzy sliding control of single-phase PV grid-connected inverter.

    Science.gov (United States)

    Fei, Juntao; Zhu, Yunkai

    2017-01-01

    In this paper, an adaptive fuzzy sliding mode controller is proposed to control a two-stage single-phase photovoltaic (PV) grid-connected inverter. Two key technologies are discussed in the presented PV system. An incremental conductance method with adaptive step is adopted to track the maximum power point (MPP) by controlling the duty cycle of the controllable power switch of the boost DC-DC converter. An adaptive fuzzy sliding mode controller with an integral sliding surface is developed for the grid-connected inverter where a fuzzy system is used to approach the upper bound of the system nonlinearities. The proposed strategy has strong robustness for the sliding mode control can be designed independently and disturbances can be adaptively compensated. Simulation results of a PV grid-connected system verify the effectiveness of the proposed method, demonstrating the satisfactory robustness and performance.

  7. Real field mission profile oriented design of a SiC-based PV-inverter application

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Christian; Blaabjerg, Frede; Wang, Huai

    2013-01-01

    This paper introduces a real field mission profile oriented design tool for the new generation of grid connected PV-inverters applications based on SiC-devices. The proposed design tool consists of a grid connected PV-inverter model, an ElectroThermal model, a converter safe operating area (SOA...... Zth_H in order to perform in a safe mode for the whole operating range. Furthermore, the proposed design tool considers the mission profile (the measured solar irradiance and ambient temperature) from the real field where the converter will operate. Thus, a realistic loading of the converter devices......) model, a mission profile model and an the evaluation block. The PV-system model involves a three level bipolar switch neutral point clamped (3L-BS NPC) inverter connected to the three phase grid through a LCL-filter. Moreover, the SOA model calculates the required converter heatsink thermal impedance...

  8. A Modified Droop Control Method for Parallel-Connected Current Source Inverters

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2016-01-01

    In this paper, a novel control method was proposed for current source inverters under the grid-connected working mode. The control scheme is based on a modified droop control method, with an additional current reference signal that will be generated instead of the voltage reference. Hence......, there is only a current control loop with droop control in the whole control scheme without voltage control loop. So it is very suitable for grid-connected current source inverter which will simplify the design of the control scheme and combine the advantage of droop control. The parallel configuration...... is widely used to acquire high power demand, but the circulating current problem is a key issue that should be considered. In this paper, a simulation based on parallel current source inverters using the proposed control scheme is provided. Simulation results showed that a good circulating current...

  9. Leakage current analysis of single-phase transformer-less grid-connected PV inverters

    DEFF Research Database (Denmark)

    Ma, Lin; Kerekes, Tamas; Teodorescu, Remus

    2016-01-01

    Transformer-less string PV inverter is getting more and more widely utilized due to its higher efficiency, smaller volume and weight. However, without the galvanic isolation, the leakage current limitation and operation safety became the key issues of transformer-less inverters. This paper...... simplifies the leakage current generation circuit model and presents a leakage current estimation method both in real time and frequency domain. It shows that the leakage current is related to the circuit stray parameters, output filter and common mode voltage. Furthermore, with the proposed analysis method......, the leakage current generation of H-bridge with different modulation methods and HERIC inverter are discussed individually. At last, the presented method has been verified via simulation....

  10. Comparative Study of Fault Diagnostic Methods in Voltage Source Inverter Fed Three Phase Induction Motor Drive

    Science.gov (United States)

    Dhumale, R. B.; Lokhande, S. D.

    2017-05-01

    Three phase Pulse Width Modulation inverter plays vital role in industrial applications. The performance of inverter demeans as several types of faults take place in it. The widely used switching devices in power electronics are Insulated Gate Bipolar Transistors (IGBTs) and Metal Oxide Field Effect Transistors (MOSFET). The IGBTs faults are broadly classified as base or collector open circuit fault, misfiring fault and short circuit fault. To develop consistency and performance of inverter, knowledge of fault mode is extremely important. This paper presents the comparative study of IGBTs fault diagnosis. Experimental set up is implemented for data acquisition under various faulty and healthy conditions. Recent methods are executed using MATLAB-Simulink and compared using key parameters like average accuracy, fault detection time, implementation efforts, threshold dependency, and detection parameter, resistivity against noise and load dependency.

  11. A Grid Connected Transformerless Inverter and its Model Predictive Control Strategy with Leakage Current Elimination Capability

    Directory of Open Access Journals (Sweden)

    J. Fallah Ardashir

    2017-06-01

    Full Text Available This paper proposes a new single phase transformerless Photovoltaic (PV inverter for grid connected systems. It consists of six power switches, two diodes, one capacitor and filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the source. This results in constant common mode voltage and zero leakage current. Model Predictive Controller (MPC technique is used to modulate the converter to reduce the output current ripple and filter requirements. The main advantages of this inverter are compact size, low cost, flexible grounding configuration. Due to brevity, the operating principle and analysis of the proposed circuit are presented in brief. Simulation and experimental results of 200W prototype are shown at the end to validate the proposed topology and concept. The results obtained clearly verifies the performance of the proposed inverter and its practical application for grid connected PV systems.

  12. A Hybrid, Current-Source/Voltage-Source Power Inverter Circuit

    DEFF Research Database (Denmark)

    Trzynadlowski, Andrzej M.; Patriciu, Niculina; Blaabjerg, Frede

    2001-01-01

    A combination of a large current-source inverter and a small voltage-source inverter circuits is analyzed. The resultant hybrid inverter inherits certain operating advantages from both the constituent converters. In comparison with the popular voltage-source inverter, these advantages include...... reduced switching losses, improved quality of output current waveforms, and faster dynamic response to current control commands. Description of operating principles and characteristics of the hybrid inverter is illustrated with results of experimental investigation of a laboratory model....

  13. A Single Switch Dual Output Non-Isolated Boost Converter

    DEFF Research Database (Denmark)

    Klimczak, Pawel; Munk-Nielsen, Stig

    2008-01-01

    There are many applications for high gain dc-dc converters. In several of these applications galvanic isolation is not required, but there are some safety issues regarding missing isolation and leakage current. Usage of a half-bridge inverter and a dual dc-link may solve this issues. In this paper...

  14. Towards Efficient Positional Inverted Index †

    Directory of Open Access Journals (Sweden)

    Petr Procházka

    2017-02-01

    Full Text Available We address the problem of positional indexing in the natural language domain. The positional inverted index contains the information of the word positions. Thus, it is able to recover the original text file, which implies that it is not necessary to store the original file. Our Positional Inverted Self-Index (PISI stores the word position gaps encoded by variable byte code. Inverted lists of single terms are combined into one inverted list that represents the backbone of the text file since it stores the sequence of the indexed words of the original file. The inverted list is synchronized with a presentation layer that stores separators, stop words, as well as variants of the indexed words. The Huffman coding is used to encode the presentation layer. The space complexity of the PISI inverted list is O ( ( N − n ⌈ log 2 b N ⌉ + ( ⌊ N − n α ⌋ + n × ( ⌈ log 2 b n ⌉ + 1 where N is a number of stems, n is a number of unique stems, α is a step/period of the back pointers in the inverted list and b is the size of the word of computer memory given in bits. The space complexity of the presentation layer is O ( − ∑ i = 1 N ⌈ log 2 p i n ( i ⌉ − ∑ j = 1 N ′ ⌈ log 2 p j ′ ⌉ + N with respect to p i n ( i as a probability of a stem variant at position i, p j ′ as the probability of separator or stop word at position j and N ′ as the number of separators and stop words.

  15. EMI performance comparison of two-level and three-level inverters in small dc-link capacitors based motor drives

    DEFF Research Database (Denmark)

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

    2012-01-01

    The size of passive components in an adjustable speed drive can be reduced by using small dc-link capacitors. The EMI filter in the drive also consists of passive components. The size of the filter can be reduced by using a three-level inverter, which can have low output voltage distortion. However......, the three-level inverter based on small dc-link capacitors requires a PWM strategy to maintain neutral-point voltage balance. In this paper, the common mode voltage, which is the determining factor for the EMI filter size, is analyzed for a virtual-vector-based PWM strategy. The common mode voltage......, the shaft voltage, and the conducted emission for the small dc-link capacitor based three-level inverter are compared with that of the two-level inverter operated with space vector PWM strategy. Experimental results for the common mode voltage, the shaft voltage, and the conducted emission are presented...

  16. A comparison of dual-energy X-ray absorptiometry, air displacement plethysmography and A-mode ultrasound to assess body composition in college-age adults.

    Science.gov (United States)

    Johnson, Kelly E; Miller, Brian; Gibson, Ann L; McLain, Trisha A; Juvancic-Heltzel, Judith A; Kappler, Rachele M; Otterstetter, Ronald

    2017-11-01

    There is currently a dearth of scientific literature exploring the agreement of A-mode ultrasound (US) body composition analysis with dual-energy X-ray absorptiometry (DXA) and air displacement plethysmography (ADP). To investigate the agreement of US with DXA and ADP for estimating fat mass (FM) and fat-free mass (FFM). College-age men (n = 33) and women (n = 41) volunteered to participate in this study. Participants were instructed to adhere to the following pretest protocol: refrain from food and drink 12 h prior to testing and wear tight fitting clothing. Body composition (BCA) was assessed using US, DXA and ADP in accordance with the respective manufacturer's guidelines. Two-way mixed-model AVOVA and Bland and Altman techniques were applied to explore agreement for FM and FFM among the three methods: US, ADP and DXA and by sex. There was no statistically significant effect by sex for either FM or FFM across all BCA comparisons (P = 0·504 and 0·510, respectively). US was not statistically different from ADP for FM and FFM (P ≈ 1·00). However, for FM and FFM, there were significant differences between DXA and both US and ADP (P≤0·001). The Bland and Altman analyses revealed large individual differences for all BCA. There was statistical agreement between US and ADP for FM and FFM but lack of agreement for US and ADP when compared to DXA. However, the large limits of agreement between methods warrant caution in generalizing these findings. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  17. Leakage Current Elimination of Four-Leg Inverter for Transformerless Three-Phase PV Systems

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; He, Ran; Jian, Jiamin

    2016-01-01

    Eliminating the leakage current is one of the most important issues for transformerless three phase photovoltaic (PV) systems. In this paper, the leakage current elimination of a three-phase four-leg PV inverter is investigated. With the common mode loop model established, the generation mechanism...... of the leakage current is clearly identified. Different typical carrier-based modulation methods and their corresponding common mode voltages are discussed. A new modulation strategy with Boolean logic function is proposed to achieve the constant common mode voltage for the leakage current reduction. Finally...

  18. Lower-Temperature Invert Design For Diffusion Barrier

    International Nuclear Information System (INIS)

    Bruce Stanley

    2001-01-01

    The objective of this analysis is to advance the state of the subsurface facilities design to primarily support the ''Yucca Mountain Science and Engineering Report'' (DOE 2001) and to also support the preparation and revision of System Description Document's Section 2 system descriptions (CRWMS M and O 2001, pp. 9 and 11). The results may also eventually support the License Application (CRWMS M and O 2001, p. 3). The Performance Assessment Department will be the primary user of the information generated and will be used in abstraction modeling for the lower-temperature scenario (CRWMS M and O 200 1, p. 27). This analysis will evaluate the invert relative to the lower- and higher-temperature conditions in accordance with the primary tasks below. Invert design is a major factor in allowing water entering the drift to pass freely and enter the drift floor without surface ponding and in limiting diffusive transport into the host rock. Specific cost effective designs will be conceptualized under the new lower-temperature conditions in this analysis. Interfacing activities and all aspects of Integrated Safety Management and Nuclear Culture principles are included in this work scope by adhering to the respective principles during this design activity and by incorporating safety into the design analysis (CRWMS M and O 2001, p. 8). Primary tasks of this analysis include identifying available design information from existing sources on the invert as a diffusive barrier, developing concepts that reduce the amount steel, and developing other design features that accommodate both lower- and higher-temperature operating modes (CRWMS M and O 2001, p.16)

  19. PWM Regulation of Grid-Tied PV System on the Base of Photovoltaic-Fed Diode-Clamped Inverters

    Directory of Open Access Journals (Sweden)

    Oleschuk V.I.

    2015-12-01

    Full Text Available Investigation of grid-tied photovoltaic system on the base of two diode-clamped inverters, controlled by specific algorithms of pulse-width modulation (PWM, has been done. This system includes two strings of photovoltaic panels feeding two diode-clamped inverters. The outputs of inverters are connected with the corresponding windings on the primary side of three-phase transformer, connected with a grid. In order to reduce phase voltage distortion and to increase efficiency of operation of the system, special scheme of control and modulation of inverters has been used, providing minimization of common-mode voltages and voltage waveforms symmetries under different operating conditions. Detailed simulation of processes in this photovoltaic-fed power conversion system has been executed. The results of simulations verify good performance of photovoltaic system regulated in accordance with specific strategy of control and modulation.

  20. New strategy for eliminating zero-sequence circulating current between parallel operating three-level NPC voltage source inverters

    DEFF Research Database (Denmark)

    Li, Kai; Dong, Zhenhua; Wang, Xiaodong

    2018-01-01

    buses, that are operating in parallel. First, an equivalent model of ZSCC in a three-phase three-level NPC inverter paralleled system is developed. Second, on the basis of the analysis of the excitation source of ZSCCs, i.e., the difference in common mode voltages (CMVs) between paralleled inverters......, the ZCMV-PWM method is presented to reduce CMVs, and a simple electric circuit is adopted to control ZSCCs and neutral point potential. Finally, simulation and experiment are conducted to illustrate effectiveness of the proposed strategy. Results show that ZSCCs between paralleled inverters can...... be eliminated effectively under steady and dynamic states. Moreover, the proposed strategy exhibits the advantage of not requiring carrier synchronization. It can be utilized in inverters with different types of filter....

  1. Origin-Dependent Inverted-Repeat Amplification: Tests of a Model for Inverted DNA Amplification.

    Directory of Open Access Journals (Sweden)

    Bonita J Brewer

    2015-12-01

    Full Text Available DNA replication errors are a major driver of evolution--from single nucleotide polymorphisms to large-scale copy number variations (CNVs. Here we test a specific replication-based model to explain the generation of interstitial, inverted triplications. While no genetic information is lost, the novel inversion junctions and increased copy number of the included sequences create the potential for adaptive phenotypes. The model--Origin-Dependent Inverted-Repeat Amplification (ODIRA-proposes that a replication error at pre-existing short, interrupted, inverted repeats in genomic sequences generates an extrachromosomal, inverted dimeric, autonomously replicating intermediate; subsequent genomic integration of the dimer yields this class of CNV without loss of distal chromosomal sequences. We used a combination of in vitro and in vivo approaches to test the feasibility of the proposed replication error and its downstream consequences on chromosome structure in the yeast Saccharomyces cerevisiae. We show that the proposed replication error-the ligation of leading and lagging nascent strands to create "closed" forks-can occur in vitro at short, interrupted inverted repeats. The removal of molecules with two closed forks results in a hairpin-capped linear duplex that we show replicates in vivo to create an inverted, dimeric plasmid that subsequently integrates into the genome by homologous recombination, creating an inverted triplication. While other models have been proposed to explain inverted triplications and their derivatives, our model can also explain the generation of human, de novo, inverted amplicons that have a 2:1 mixture of sequences from both homologues of a single parent--a feature readily explained by a plasmid intermediate that arises from one homologue and integrates into the other homologue prior to meiosis. Our tests of key features of ODIRA lend support to this mechanism and suggest further avenues of enquiry to unravel the origins

  2. Origin-Dependent Inverted-Repeat Amplification: Tests of a Model for Inverted DNA Amplification.

    Science.gov (United States)

    Brewer, Bonita J; Payen, Celia; Di Rienzi, Sara C; Higgins, Megan M; Ong, Giang; Dunham, Maitreya J; Raghuraman, M K

    2015-12-01

    DNA replication errors are a major driver of evolution--from single nucleotide polymorphisms to large-scale copy number variations (CNVs). Here we test a specific replication-based model to explain the generation of interstitial, inverted triplications. While no genetic information is lost, the novel inversion junctions and increased copy number of the included sequences create the potential for adaptive phenotypes. The model--Origin-Dependent Inverted-Repeat Amplification (ODIRA)-proposes that a replication error at pre-existing short, interrupted, inverted repeats in genomic sequences generates an extrachromosomal, inverted dimeric, autonomously replicating intermediate; subsequent genomic integration of the dimer yields this class of CNV without loss of distal chromosomal sequences. We used a combination of in vitro and in vivo approaches to test the feasibility of the proposed replication error and its downstream consequences on chromosome structure in the yeast Saccharomyces cerevisiae. We show that the proposed replication error-the ligation of leading and lagging nascent strands to create "closed" forks-can occur in vitro at short, interrupted inverted repeats. The removal of molecules with two closed forks results in a hairpin-capped linear duplex that we show replicates in vivo to create an inverted, dimeric plasmid that subsequently integrates into the genome by homologous recombination, creating an inverted triplication. While other models have been proposed to explain inverted triplications and their derivatives, our model can also explain the generation of human, de novo, inverted amplicons that have a 2:1 mixture of sequences from both homologues of a single parent--a feature readily explained by a plasmid intermediate that arises from one homologue and integrates into the other homologue prior to meiosis. Our tests of key features of ODIRA lend support to this mechanism and suggest further avenues of enquiry to unravel the origins of interstitial

  3. Addressable inverter matrix for process and device characterization

    Science.gov (United States)

    Buehler, M. G.; Sayah, H. R.

    1985-01-01

    The addressable inverter matrix consists of 222 inverters each accessible with the aid of a shift register. The structure has proven useful in characterizing the variability of inverter transfer curves and in diagnosing processing faults. For good 3-micron CMOS bulk inverters investigated, the percent standard deviation of the inverter threshold voltage was less than one percent and the inverter gain (the slope of the inverter transfer curve at the inverter threshold vltage) was less than 3 percent. The average noise margin for the inverters was near 2 volts for a power supply voltage of 5 volts. The specific faults studied included undersize pull-down transistor widths and various open contacts in the matrix.

  4. An SCR inverter for electric vehicles

    Science.gov (United States)

    Latos, T.; Bosack, D.; Ehrlich, R.; Jahns, T.; Mezera, J.; Thimmesch, D.

    1980-01-01

    An inverter for an electric vehicle propulsion application has been designed and constructed to excite a polyphase induction motor from a fixed propulsion battery source. The inverter, rated at 35kW peak power, is fully regenerative and permits vehicle operation in both the forward and reverse directions. Thyristors are employed as the power switching devices arranged in a dc bus commutated topology. This paper describes the major role the controller plays in generating the motor excitation voltage and frequency to deliver performance similar to dc systems. Motoring efficiency test data for the controller are presented. It is concluded that an SCR inverter in conjunction with an ac induction motor is a viable alternative to present dc vehicle propulsion systems on the basis of performance and size criteria.

  5. Feasibility of a dual regime gyrotron

    International Nuclear Information System (INIS)

    Sawant, Ashwini; Jain, Prerit; Kartikeyan, M.V.

    2012-01-01

    The design concept of a 42/84 GHz, 500 kW, CW, dual-regime gyrotron for ECRH of plasma in an experimental Tokamak will be presented in this paper. Operation at 42 GHz is fundamental where as that in 84 GHz will be second harmonic so that a similar guidance system will be retained for dual regime operation. In this paper, the mode competition and mode selection procedures are presented for such a dual regime operation. Cold cavity design and self-consistent calculations will be carried out for power and efficiencies. (author)

  6. The Explicit Determinations Of Dual Plane Curves And Dual Helices In Terms Of Its Dual Curvature And Dual Torsion

    OpenAIRE

    Lee Jae Won; Choi Jin Ho; Jin Dae Ho

    2014-01-01

    In this paper, we give the explicit determinations of dual plane curves, general dual helices and dual slant helices in terms of its dual curvature and dual torsion as a fundamental theory of dual curves in a dual 3-space

  7. Analysis and Design of Improved Weighted Average Current Control Strategy for LCL-Type Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Han, Yang; Li, Zipeng; Yang, Ping

    2017-01-01

    The LCL grid-connected inverter has the ability to attenuate the high-frequency current harmonics. However, the inherent resonance of the LCL filter affects the system stability significantly. To damp the resonance effect, the dual-loop current control can be used to stabilize the system. The grid...... Control Strategy for LCL-Type Grid-Connected Inverters. Available from: https://www.researchgate.net/publication/313734269_Analysis_and_Design_of_Improved_Weighted_Average_Current_Control_Strategy_for_LCL-Type_Grid-Connected_Inverters [accessed Apr 20, 2017]....... current plus capacitor current feedback system is widely used for its better transient response and high robustness against the grid impedance variations. While the weighted average current (WAC) feedback scheme is capable to provide a wider bandwidth at higher frequencies but show poor stability...

  8. Evaluation of Three-Phase Transformerless Photovoltaic Inverter Topologies

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Liserre, Marco; Teodorescu, Remus

    2009-01-01

    This paper analyzes and compares three transformerless photovoltaic inverter topologies for three-phase grid connection with the main focus on the safety issues that result from the lack of galvanic isolation. A common-mode model, valid at frequencies lower than 50 kHz, is adopted to study...... the leakage current paths. The model is validated by both simulation and experimental results. These will be used to compare the selected topologies, and to explain the influence of system unbalance and the neutral conductor inductance on the leakage current. It will be demonstrated that the later has...... a crucial influence. Finally, a comparison of the selected topologies is carried out, based on the adopted modulation, connection of the neutral and its inductance, effects of unbalance conditions, component ratings, output voltage levels, and filter size....

  9. Live Imaging of Shoot Meristems on an Inverted Confocal Microscope Using an Objective Lens Inverter Attachment

    Science.gov (United States)

    Nimchuk, Zachary L.; Perdue, Tony D.

    2017-01-01

    Live imaging of above ground meristems can lead to new insights in plant development not possible from static imaging of fixed tissue. The use of an upright confocal microscope offers several technical and biological advantages for live imaging floral or shoot meristems. However, many departments and core facilities possess only inverted confocal microscopes and lack the funding for an additional upright confocal microscope. Here we show that imaging of living apical meristems can be performed on existing inverted confocal microscopes with the use of an affordable and detachable InverterScope accessory. PMID:28579995

  10. Live Imaging of Shoot Meristems on an Inverted Confocal Microscope Using an Objective Lens Inverter Attachment.

    Science.gov (United States)

    Nimchuk, Zachary L; Perdue, Tony D

    2017-01-01

    Live imaging of above ground meristems can lead to new insights in plant development not possible from static imaging of fixed tissue. The use of an upright confocal microscope offers several technical and biological advantages for live imaging floral or shoot meristems. However, many departments and core facilities possess only inverted confocal microscopes and lack the funding for an additional upright confocal microscope. Here we show that imaging of living apical meristems can be performed on existing inverted confocal microscopes with the use of an affordable and detachable InverterScope accessory.

  11. Modeling the frequency response of photovoltaic inverters

    NARCIS (Netherlands)

    Ernauli Christine Aprilia, A.; Cuk, V.; Cobben, J.F.G.; Ribeiro, P.F.; Kling, W.L.

    2012-01-01

    The increased presence of photovoltaic (PV) systems inevitably affects the power quality in the grid. This new reality demands grid power quality studies involving PV inverters. This paper proposes several frequency response models in the form of equivalent circuits. Models are based on laboratory

  12. The Internet and the Inverted Classroom.

    Science.gov (United States)

    Lage, Maureen J.; Platt, Glenn

    2000-01-01

    Describes a Web site that is for an undergraduate principles of microeconomics course and a main component of "The Inverted Classroom" in which lectures take place outside of class. Explains that the Web site is divided into four sections: (1) the classroom; (2) the desk; (3) the coffee shop; and (4) the library. (CMK)

  13. An Inverted Curriculum for CS1

    DEFF Research Database (Denmark)

    Caspersen, Michael Edelgaard

    2003-01-01

    present and discuss the inverted curriculum for our introductory object-oriented programming course, and our experiences from teaching this course for four years. We identify four levels for the systematic construction of programs, and the structure of our programming course is based on these four levels......: the modeling level, the design level, the class level, and the algorithmic level....

  14. Smart Inverters for Utility and Industry Applications

    DEFF Research Database (Denmark)

    Xue, Yaosuo; Guerrero, Josep M.

    2015-01-01

    Smart inverters are emerging with increasing renewable energy and smart grid development. While the recent work reviewed mostly focuses on defining standardized control functionalities and smart grid communication protocols, we take a holistic approach in this paper and propose a holon-type smart...

  15. Cascaded impedance networks for NPC inverter

    DEFF Research Database (Denmark)

    Li, Ding; Gao, Feng; Loh, Poh Chiang

    2010-01-01

    they are subject to the renewable sources. To date, three distinct types of impedance networks can be summarized for implementing a hybrid source impedance network, which can in principle be combined and cascaded before connected to a NPC inverter by proposed two ways. The resulting cascaded impedance network NPC...

  16. Two-Stage Series-Resonant Inverter

    Science.gov (United States)

    Stuart, Thomas A.

    1994-01-01

    Two-stage inverter includes variable-frequency, voltage-regulating first stage and fixed-frequency second stage. Lightweight circuit provides regulated power and is invulnerable to output short circuits. Does not require large capacitor across ac bus, like parallel resonant designs. Particularly suitable for use in ac-power-distribution system of aircraft.

  17. Inverter Matrix for the Clementine Mission

    Science.gov (United States)

    Buehler, M. G.; Blaes, B. R.; Tardio, G.; Soli, G. A.

    1994-01-01

    An inverter matrix test circuit was designed for the Clementine space mission and is built into the RRELAX (Radiation and Reliability Assurance Experiment). The objective is to develop a circuit that will allow the evaluation of the CMOS FETs using a lean data set in the noisy spacecraft environment.

  18. Pulse width modulation inverter with battery charger

    Science.gov (United States)

    Slicker, James M.

    1985-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

  19. Inverter-based successive approximation capacitance-to-digital converter

    KAUST Repository

    Omran, Hesham; Alhoshany, Abdulaziz; Salama, Khaled N.

    2017-01-01

    offset voltage will result in signal-dependent and parasitic-dependent conversion errors, which necessitates an op-amp-based implementation. The inverter-based SAR CDC contemplated herein provides robust, energy-efficient, and fast operation. The inverter

  20. FPGA Based Compensation Method for Correcting Distortion in Voltage Inverters

    National Research Council Canada - National Science Library

    Williamson, Kenya D

    2007-01-01

    ...) voltage source inverters. Blanking time distortion is caused by the delay inserted to prevent the short circuit that would occur if the two transistors in the same inverter leg are both on at the same time...