New solid state opening switches for repetitive pulsed power technology

Energy Technology Data Exchange (ETDEWEB)

Lyubutin, S K; Mesyats, G A; Rukin, S N; Slovikovskii, B G; Turov, A M [Russian Academy of Sciences, Ekaterinburg (Russian Federation). Inst. of Electrophysics

1997-12-31

In 1991 the authors discovered a semiconductor opening switch (SOS) effect that occurs in p{sup +}-p-n-n{sup +} silicon structures at a current density of up to 60 kA/cm{sup 2}. This effect was used to develop high-power semiconductor opening switches in intermediate inductive storage circuits. The breaking power of the opening switches was as high as 5 GW, the interrupted current being up to 45 kA, reverse voltage up to 1 MV and the current interruption time between 10 and 60 ns. The opening switches were assembled from quantity-produced Russian-made rectifying diodes type SDL with hard recovery characteristic. On the basis of experimental and theoretical investigations of the SOS effect, new SOS diodes were designed and manufactured by the Electrophysical Institute. The paper gives basic parameters of the SOS diodes. The new diodes offer higher values of interrupted current and shorter times of current interruption together with a considerable increase in the energy switching efficiency. The new SOS diodes were used to develop repetitive all-solid-state pulsed generators with an output voltage of up to 250 kV, pulse repetition rate up to 5 kHz, and pulse duration between 10 and 30 ns. (author). 2 tabs., 3 figs., 4 refs.

Plasma opening switch experiments on the Particle Beam Accelerator II

International Nuclear Information System (INIS)

Sweeney, M.A.; McDaniel, D.H.; Mendel, C.W.; Rochau, G.E.; Moore, W.B.S.; Mowrer, G.R.; Simpson, W.W.; Zagar, D.M.; Grasser, T.; McDougal, C.D.

1989-01-01

Plasma opening switch (POS) experiments have been done since 1986 on the PBFA-II ion beam accelerator to develop a rugged POS that will open rapidly ( 80%) into a high impedance (> 10 ohm) load. In a recent series of experiments on PBFA II, the authors have developed and tested three different switch designs that use magnetic fields to control and confine the injected plasma. All three configurations couple current efficiently to a 5-ohm electron beam diode. In this experimental series, the PBFA-II Delta Series, more extensive diagnostics were used than in previous switch experiments on PBFA II or on the Blackjack 5 accelerator at Maxwell Laboratories. Data from the experiments with these three switch designs is presented

Plasma opening switch with extrinsic magnetic field

CERN Document Server

Dolgachev, G; Maslennikov, D

2001-01-01

Summary form only given, as follows. We have demonstrated in series of experiments that plasma opening switch (POS) switching voltage (UPOS) is defined by energy density (w) deposited in the POS plasma. If we then consider a plasma erosion mainly responsible for the effect of POS switching (the erosion effect could be described by Hall or Child-Langmuir models) the energy density (w) could be measured as a function of a system "macro-parameter" such as the initial charging voltage of the capacity storage system (the Marx pulsed voltage generator) UMarx. The POS voltage in this case could be given by UPOS"aw=aUMarx4/7, where a is a constant. This report demonstrates that for the high-impedance POS which has limited charge density transferred through the POS plasma a"2.5 (MV3/7) with no external magnetic field applied. The use of the extrinsic magnetic field allows to increase a up to 3.6 (MV3/7) and to achieve higher voltages at the opening phase - UPOS=3.6UMarx4/7. To verify this approach set of experimental ...

Anthem simulation studies of the plasma opening switch

International Nuclear Information System (INIS)

Mason, R.J.

1993-01-01

For a deeper understanding of the physical processes governing the Plasma Opening Switch (POS) the authors use the ANTHEM 2D implicit simulation code to study: (1) ion dynamical effects on electrohydrodynamic (EHD) waves propagating along steep density interfaces in the switch plasmas. At radial interfaces where the density jumps toward the anode, these waves can drive a finger of magnetic field into the plasma toward the load. Ion dynamics can open the rear of such fingers into a wedge-like density gap. Then: (2) they examine ion effects in uniform switch plasmas. These first develop potential hill structures at the drive edge of the cathode from the competition between electron velocity advection and EHD magnetic exclusion waves. Magnetic pressure gradients at the hill periphery and EHD effects then establish a density gap propagating along the cathode with radial electron emission from its tip. Similar results are obtained under both multi-fluid and PIC modeling on the plasma components

Using Alloy to Formally Model and Reason About an OpenFlow Network Switch

OpenAIRE

Mirzaei, Saber; Bahargam, Sanaz; Skowyra, Richard; Kfoury, Assaf; Bestavros, Azer

2016-01-01

Openflow provides a standard interface for separating a network into a data plane and a programmatic control plane. This enables easy network reconfiguration, but introduces the potential for programming bugs to cause network effects. To study OpenFlow switch behavior, we used Alloy to create a software abstraction describing the internal state of a network and its OpenFlow switches. This work is an attempt to model the static and dynamic behaviour a network built using OpenFlow switches.

Experimental study on the characteristics of semiconductor opening switch

CERN Document Server

Su Jian Cang; Ding Yong Zhong; Song Zhi Min; Ding Zhen Jie; Liu Guo Zhi

2002-01-01

An experimental set-up is developed to measure the characteristics of semiconductor opening switch (SOS). The parameters, such as interruption impedance, current int eruption time, voltage gain, pulse duration and energy transfer efficiency, are studied experimentally. The experimental results show that forward pumping time and reverse pumping time are important parameters for semiconductor opening switches. The influences of forward pumping time and reverse pumping time on interruption time, voltage gain, and energy transfer efficiency are obtained. In the interruption process, the impedance variation is divided into three phases: that is rapid increasing phase, slow change phase and completely interruption phase

Wavelet Entropy-Based Traction Inverter Open Switch Fault Diagnosis in High-Speed Railways

Directory of Open Access Journals (Sweden)

Keting Hu

2016-03-01

Full Text Available In this paper, a diagnosis plan is proposed to settle the detection and isolation problem of open switch faults in high-speed railway traction system traction inverters. Five entropy forms are discussed and compared with the traditional fault detection methods, namely, discrete wavelet transform and discrete wavelet packet transform. The traditional fault detection methods cannot efficiently detect the open switch faults in traction inverters because of the low resolution or the sudden change of the current. The performances of Wavelet Packet Energy Shannon Entropy (WPESE, Wavelet Packet Energy Tsallis Entropy (WPETE with different non-extensive parameters, Wavelet Packet Energy Shannon Entropy with a specific sub-band (WPESE3,6, Empirical Mode Decomposition Shannon Entropy (EMDESE, and Empirical Mode Decomposition Tsallis Entropy (EMDETE with non-extensive parameters in detecting the open switch fault are evaluated by the evaluation parameter. Comparison experiments are carried out to select the best entropy form for the traction inverter open switch fault detection. In addition, the DC component is adopted to isolate the failure Isolated Gate Bipolar Transistor (IGBT. The simulation experiments show that the proposed plan can diagnose single and simultaneous open switch faults correctly and timely.

Experiments on microsecond conduction time plasma opening switch mechanisms

International Nuclear Information System (INIS)

Rix, W.; Coleman, M.; Miller, A.R.; Parks, D.; Robertson, K.; Thompson, J.; Waisman, E.; Wilson, A.

1993-01-01

The authors describe a series of experiments carried out on ACE 2 and ACE 4 to elucidate the mechanisms controlling the conduction and opening phases on plasma opening switches in a radial geometry with conduction times on the order of a microsecond. The results indicate both conduction and opening physics are similar to that observed on lower current systems in a coaxial geometry

Pulsed power opening switch research at the University of New Mexico

International Nuclear Information System (INIS)

Humphries, S. Jr.

1987-01-01

Opening switch research at the University of New Mexico (UNM) is directed toward moderate-current (--10 kA) devices with potential applications to high-power charged particle accelerators. Two devices with the capacity for controlling gigawatt high-voltage circuits, the grid-controlled plasma flow switch and the scanned-beam switch, are under investigation. Both switches are conceptually simple; they involve little collective physics and are within the capabilities of current technology. In the plasma flow switch, the flux of electrons into a high-voltage power gap is controlled by a low-voltage control grid. Plasma generation is external to, and independent of, the power circuit. In the closed phase, plasma fills the gap so that the switch has a low on-state impedance. Pulse repetition rates in the megahertz range should be feasible. In single-shot proof-of-principle experiments, a small area switch modulated a 3-MW circuit; a 20-ns opening time was observed. The scanned-beam switch will utilize electric field deflection to direct the power of a sheet electron beam. The beam is to be alternately scanned to two inverse diodes connected to output transmission lines. The switch is expected to generate continuous-wave pulse trains for applications such as high-frequency induction linacs. Theoretical studies indicate that 10-GW devices in the 100-MHz range with 70-percent efficiency should be technologically feasible

Preliminary studies on a plasma focus opening switch

Energy Technology Data Exchange (ETDEWEB)

Wong, C S; Moo, S P; Singh, J P [Univ. of Malaya, Kuala Lumpur (Malaysia). Physics Dept., Plasma Research Laboratory; Choi, P [Ecole Polytechnique, Palaiseau (France). Laboratoire de Physique des Milieux Ionises

1997-12-31

The small plasma focus device UNU/ICTP PFF has been modified to assess the operation of a plasma focus based long conduction (> 2 {mu}s) opening switch, with a plasma filled diode as the load. The UNU/ICTP PFF is a Mather type plasma focus device powered by a single 15 kV, 30 {mu}F capacitor delivering a peak current of 150 kA when discharged at 15 kV. The device has been optimized for reproducible focusing in various gases including deuterium, argon, carbon dioxide, helium as well as in air. In particular, the optimum operating pressure for air is between 0.5 to 1.1 mbar, whereas for argon it is between 0.3 to 3 mbar. For the operation of the UNU/ICTP PFF as an opening switch, the electrode geometry is modified to redirect the plasma motion at the end of the axial rundown phase to avoid the normal plasma focus action, and the operating regime is shifted to low pressure to favour plasma opening switch action. With air as the working gas, pressure as low as 10{sup -3} mbar was tested. At such a low pressure, a set of 12 plasma injection cable guns is used to initiate breakdown of the discharge. The design and operating principle is presented and some preliminary results obtained on the operational characteristics of this device are discussed. (author). 5 figs., 4 refs.

The experimental investigation of explosive opening switch

Energy Technology Data Exchange (ETDEWEB)

Jiande, Zhang; Huihuang, Zhong; Chuanlu, Li; Yonggui, Liu; Dongqun, Cheng; Xianyang, Peng [National Univ. of Defense Technology, Changsha (China). Dept. of Applied Physics

1997-12-31

The explosive opening switch (EOS) used in explosive-driven magnetic-flux compression generator (EMCG) circuits was investigated. It is shown that (1) under certain conditions, the EOS voltage is hardly dependent on the size of the explosive and aluminium foil used in EOS; (2) with the explosive coated by an insulator pipe, the opening effect of EOS is better; (3) by use of EOS, a pulse with 5 kA current, 100 kV voltage and 250 ns risetime has been transferred into a resistance load. (author). 12 figs., 5 refs.

The experimental investigation of explosive opening switch

International Nuclear Information System (INIS)

Zhang Jiande; Zhong Huihuang; Li Chuanlu; Liu Yonggui; Cheng Dongqun; Peng Xianyang

1996-01-01

The explosive opening switch (EOS) used in explosive-driven magnetic-flux compression generator (EMCG) circuits was investigated. It is shown that (1) under certain conditions, the EOS voltage is hardly dependent on the size of the explosive and aluminium foil used in EOS; (2) with the explosive coated by an insulator pipe, the opening effect of EOS is better; (3) by use of EOS, a pulse with 5 kA current, 100 kV voltage and 250 ns risetime has been transferred into a resistance load. (author). 12 figs., 5 refs

High voltage, high power operation of the plasma erosion opening switch

International Nuclear Information System (INIS)

Neri, J.M.; Boller, J.R.; Ottinger, P.F.; Weber, B.V.; Young, F.C.

1987-01-01

A Plasma Erosion Opening Switch (PEOS) is used as the opening switch for a vacuum inductive storage system driven by a 1.8-MV, 1.6-TW pulsed power generator. A 135-nH vacuum inductor is current charged to ∼750 kA in 50 ns through the closed PEOS which then opens in <10 ns into an inverse ion diode load. Electrical diagnostics and nuclear activations from ions accelerated in the diode yield a peak load voltage (4.25 MV) and peak load power (2.8 TW) that are 2.4 and 1.8 times greater than ideal matched load values for the same generator pulse

Long conduction time plasma opening switch experiments at Sandia National Laboratories

International Nuclear Information System (INIS)

Savage, M.E.; Simpson, W.W.; Cooper, G.W.; Usher, M.A.

1993-01-01

Sandia National Laboratories has undertaken an ambitious program to reduce the size and cost of large pulsed power drivers. The program basis is inductive energy storage and Plasma Opening Switches (POS). Inductive energy storage has well known advantages, including increased efficiency and reduced stress on the vacuum interface. The Sandia approach is to retain the reliable and efficient Marx generator and the temporal pulse compression of the water dielectric capacitor. A triggered closing switch, developed at Sandia, transfers the capacitor charge into the energy storage inductor. This approach has several advantages, including relaxed requirements on Marx jitter and inductance, and much faster current risetime in the energy storage inductor. The POS itself is the key to the Sandia program. The switch design uses an auxiliary magnetic field to inject the plasma and hold it in place during conduction. After opening begins, the self magnetic field of the power pulse pushes on the plasma to increase the opened gap. The authors use magnetic pressure because they desire POS gaps of several cm. Typical plasma opening switches do not achieve large gaps. Improved opening allows more efficient transfer to loads. They present results from recent experiments at Sandia. Their driver presently supplies 650 kA with a 240 ns risetime to the input of the POS. The storage inductor is a 17 Ohm magnetically insulated transmission line (MITL) that is five meters long. They discuss the ways in which magnetic field influences the POS, and the ways in which they control the magnetic fields

Application of plasma erosion opening switches to high power accelerators for pulse compression and power multiplication

International Nuclear Information System (INIS)

Meyer, R.A.; Boller, J.R.; Commisso, R.J.

1983-01-01

A new vacuum opening switch called a plasma erosion opening switch is described. A model of its operation is presented and the energy efficiency of such a switch is discussed. Recent high power experiments on the Gamble II accelerator are described and compared to previous experiments

Methodology, Measurement and Analysis of Flow Table Update Characteristics in Hardware OpenFlow Switches

KAUST Repository

Kuźniar, Maciej

2018-02-15

Software-Defined Networking (SDN) and OpenFlow are actively being standardized and deployed. These deployments rely on switches that come from various vendors and differ in terms of performance and available features. Understanding these differences and performance characteristics is essential for ensuring successful and safe deployments.We propose a systematic methodology for SDN switch performance analysis and devise a series of experiments based on this methodology. The methodology relies on sending a stream of rule updates, while relying on both observing the control plane view as reported by the switch and probing the data plane state to determine switch characteristics by comparing these views. We measure, report and explain the performance characteristics of flow table updates in six hardware OpenFlow switches. Our results describing rule update rates can help SDN designers make their controllers efficient. Further, we also highlight differences between the OpenFlow specification and its implementations, that if ignored, pose a serious threat to network security and correctness.

Electron beam potential measurements on an inductive-store, opening-switch accelerator

International Nuclear Information System (INIS)

Riordan, J.C.; Goyer, J.R.; Kortbawi, D.; Meachum, J.S.; Mendenhall, R.S.; Roth, I.S.

1993-01-01

Direct measurement of the accelerating potential in a relativistic electron beam accelerator is difficult, particularly when the diode is downstream from a plasma opening switch. An indirect potential measurement can be obtained from the high energy tail of the bremsstrahlung spectrum generated as the electron beam strikes the anode. The authors' time-resolved spectrometer contains 7 silicon pin diode detectors filtered with 2 to 15 mm of lead to span an electron energy range of 0.5 to 2 MeV. A Monte-Carlo transport code was used to provide calibration curves, and the resulting potential measurements have been confirmed in experiments on the PITHON accelerator. The spectrometer has recently been deployed on PM1, an inductive-store, opening-switch testbed. The diode voltage measurements from the spectrometer are in good agreement with the diode voltage measured upstream and corrected using transmission line relations. The x-ray signal and spectral voltage rise 10 ns later than the corrected electrical voltage, however, indicating plasma motion between the opening switch and the diode

GIT 16: megajoule pulsed generator with plasma opening switch for Z-pinch loads

International Nuclear Information System (INIS)

Bugaev, S.P.; Volkov, A.M.; Kim, A.A.

1997-01-01

Megajoule complex GIT 16 reserved for perfecting technology of forming powerful impulse with the help of intermediate inductive storage and break contact in the form of plasma opening switches and for investigating of irradiating loading of Z-pinch type is presented. The characteristics of isolated complex elements are given and basic results characterizing microsecond plasma opening switches at the current level of same M A are described

Open-switch fault detection method of an NPC converter for wind turbine systems

DEFF Research Database (Denmark)

Lee, June-Seok; Lee, Kyo-Beum; Blaabjerg, Frede

2013-01-01

In wind turbine generation (WTG) systems, the neutral-point-clamped (NPC) topology is widely used as the part of a back-to-back converter since the three-level NPC topology has more advantages than the conventional two-level inverter especially for high power. There are twelve switches in the NPC......-switch detection method of the NPC converter is different from that of the NPC inverter due to the different current paths of the NPC converter. This paper proposes the open-switch fault detection method of the NPC converter connected the permanent-magnet synchronous generator (PMSG). Moreover, the open...

Two dimensional Hall MHD modeling of a plasma opening switch with density inhomogeneities

Energy Technology Data Exchange (ETDEWEB)

Zabaidullin, O [Kurchatov Institute, Moscow (Russian Federation); Chuvatin, A; Etlicher, B [Ecole Polytechnique, Palaiseau (France). Laboratoire de Physique des Milieux Ionises

1997-12-31

The results of two-dimensional numerical modeling of the Plasma Opening Switch in the MHD framework with Hall effect are presented. An enhanced Hall diffusion coefficient was used in the simulations. Recent experiments justify the application of this approach. The result of the modeling also correlates better with the experiment than in the case of the classical diffusion coefficient. Numerically generated pictures propose a switching scenario in which the translation between the conduction and opening phases can be explained by an abrupt `switching on` and further domination of the Hall effect at the end of the conduction phase. (author). 3 figs., 6 refs.

Open data for water-related operational services, the SWITCH-ON approach

Science.gov (United States)

Mazzoli, Paolo; Bagli, Stefano; Valerio, Luzzi; Broccoli, Davide; Piccinini, Francesca

2017-04-01

Recently, a collaborative project started called SWITCH-ON (EU FP7 project No 603587) coordinated by SMHI (http://water-switch-on.eu/) as part of the contemporary European movement imposed by the INSPIRE directive and the Open Data Strategy. Among It's R&D activities GECOsistema develops and expands inside SWITCH-ON a set of online services to tackle major water related issues, from reservoir and irrigation supply, to hydrological change adaptation and hydropower potential mapping. Here we present major releases of APRIL, HyCAW and High-resolution European HydroPower Atlas; all of which make intense use of open data. APRIL is a tool for seasonal run-off forecasts, that takes advantage of open datasets or low-cost data and performs forecasts through calibrated machine learning algorithms. HyCAW is a wizard that supports the assessment of adaptation options to cope with change in the temporal distribution of water availability as well as in the total water quantity. EU HPA provides all relevant information necessary to appraise the feasibility of a micro-hydropower plant at a specific site, taking into account hydrological as well as technical and economic factors. All the tools share a common vision of the project to address water concerns and currently untapped potential of open data for improved water management across the EU. Users are guided through a Web GIS interface, created using open source Web Mapping Applications, Open-Layers and Map Server, to explore available hydrological information in the area of interest, plot available data, perform analysis, and get reports and statistics.

Performance of magnetically-injected-plasma opening switches on the particle beam fusion accelerator 2

International Nuclear Information System (INIS)

Rochau, G.E.; McDaniel, D.H.; Mendel, C.W.; Sweeney, M.A.; Moore, W.B.S.; Mowrer, G.R.; Zagar, D.M.

1990-01-01

Plasma opening switch (POS) experiments have been performed on the PBFA II ion beam accelerator to develop a switch which will provide voltage and power gain to an applied-B lithium ion diode. These experiments have successfully coupled power to electron and ion beam diodes using a Magnetically-Injected-Plasma (MIP) POS. Carbon plasma with electron densities of 1 x 10 12 to 2 x 10 13 /cm 3 have been injected from the anode into the 8 cm gap of the 20-ohm Magnetically-Insulated-Transmission Line (MITL) of PBFA II along a B r,z magnetic field. The MIP switch uses the inertia of the plasma to keep the switch closed and the magnetic pressure of B θ from the conduction current to open the switch. The configuration of the injecting magnetic field and the plasma source has a significant effect on the efficiency of coupling power to high impedance loads. Plasma near the center of the injecting magnetic field limits the opening impedance of the switch and subsequently the power delivered to the load. The axial location of the switch with respect to the load has also been identified as a critical parameter in increasing the coupling efficiency. A length of 10 to 20 cm of MITL between the POS and the load has increased the power delivered to the load. Data on switch performance with high impedance loads and factors which improved performance are discussed

Study of opening switch characteristics of a plasma focus

International Nuclear Information System (INIS)

Rhee, M.J.; Schneider, R.F.

1985-01-01

It is shown that a current charged transmission line and an opening switch can be used as an inductive energy storage system to produce a high power pulse. A plasma focus device, in which a transmission line is inserted in series with the capacitor bank and a coaxial gun, is considered as an inductive energy storage system. The m = 0 instability in the plasma focus is utilized as an opening switch and the disrupted plasma column is considered as bipolar diode. The system is described preferably by the transmission line theory rather than the lumped circuit theory. The relationship between the output voltage and the current drop is given by V = ΔIZ, where Z is the characteristic impedance of the transmission line. The current drop ΔI depends on the mismatched load impedance of the plasma diode which is governed by nature of the m = 0 instability

Performance of a plasma opening switch in positive polarity on Gamble I using flashboard plasma sources

International Nuclear Information System (INIS)

Renk, T.J.

1995-01-01

The successful development of the Plasma Opening Switch (POS) for inductive storage applications has been largely confined to negative polarity operation. Some models of POS behavior suggest that this is because in a positive polarity coaxial configuration, the weaker magnetic field at the cathode position retards the switch opening process. This article describes experiments in which both conductor radii in the POS region were significantly reduced. Anode- and cathode-side current monitors indicate that voltages greater than open-circuit are generated at the POS position, but there is a significant amount of electron flow out of the POS, depending upon load impedance. Flow impedance analysis indicates that a relatively small gap appears in the POS plasma after switch opening. Switch performance is also compared between flashboard and carbon gun plasma sources, with the latter operated both in positive and negative polarity

High explosive driven plasma opening switches

International Nuclear Information System (INIS)

Greene, A.E.; Bowers, R.L.; Brownell, J.H.; Goforth, J.H.; Oliphant, T.A.; Weiss, D.L.

1983-01-01

A joint theoretical and experimental effort is underway to understand and improve upon the performance of high explosive driven plasma opening switches such as those first described by Pavlovskii et al. We have modeled these switches in both planar and cylindrical geometry using a one dimensional Lagrangian MHD code. This one-dimensional analysis is now essentially complete. It has shown that simple, one-dimensional, compression of the current-carrying channel can explain the observed resistance increases during the time of flight of the HE detonation products. Our calculations imply that ionization plays an important role as an energy sink and the performance of these switches might be improved by a judicious choice of gases. We also predict improved performance by lowering the pressure in the plasma channel. The bulk of our experimental effort to date has been with planar switches. We have worked with current densities of 0.25 to 0.4 MA/cm and have observed resistance increases of 40 to 60 mΩ. Significant resistance increases are observed later than the time of flight of the HE detonation products. We suggest that these resistance increases are due to mixing between the hot plasma and the relatively cooler detonation products. Such mixing is not included in the 1-D, Lagrangian code. We are presently beginning a computational effort with a 2-D Eulerian code. The status of this effort is discussed. Experimentally we have designed an apparatus that will permit us to test the role of different gases and pressures. This system is also in a planar geometry, but the plasma channel is doughnut shaped, permitting us to avoid edge effects associated with the planar rectangular geometry. The first experiments with this design are quite encouraging and the status of this effort is also discussed

Open-Switch Fault Diagnosis and Fault Tolerant for Matrix Converter with Finite Control Set-Model Predictive Control

DEFF Research Database (Denmark)

Peng, Tao; Dan, Hanbing; Yang, Jian

2016-01-01

To improve the reliability of the matrix converter (MC), a fault diagnosis method to identify single open-switch fault is proposed in this paper. The introduced fault diagnosis method is based on finite control set-model predictive control (FCS-MPC), which employs a time-discrete model of the MC...... topology and a cost function to select the best switching state for the next sampling period. The proposed fault diagnosis method is realized by monitoring the load currents and judging the switching state to locate the faulty switch. Compared to the conventional modulation strategies such as carrier......-based modulation method, indirect space vector modulation and optimum Alesina-Venturini, the FCS-MPC has known and unchanged switching state in a sampling period. It is simpler to diagnose the exact location of the open switch in MC with FCS-MPC. To achieve better quality of the output current under single open...

Microsecond plasma opening switch experiments on GIT-4

Energy Technology Data Exchange (ETDEWEB)

Bystritskij, V M; Lisitsyn, I V; Sinebryukhov, A A; Sinebryukhov, V A [Russian Academy of Sciences, Tomsk (Russian Federation). Inst. of Electrophysics; Kim, A A; Kokshenev, V A; Koval` chuk, B M [Russian Academy of Sciences, Tomsk (Russian Federation). High Current Electronics Inst.

1997-12-31

The plasma opening switch (POS) operation at the current level up to 2 MA was studied at the terawatt power GIT-4 generator. The experiments are described in which the electrode diameter and the strength of the applied magnetic field were varied, and different plasma sources were used. It is shown that the high voltage / low impedance switch operation can be achieved if the linear current density at the POS cathode does not exceed 20 kA/cm. This value limits the maximum cathode diameter of the magnetically insulated transmission line. The anode diameter is limited by the requirement of no gap closure with a dense electrode plasma. The application of external magnetic field decreases the plasma density necessary for achieving a long POS conduction time operation regime. (J.U.). 1 tab., 4 refs.

Microsecond plasma opening switch experiments on GIT-4

International Nuclear Information System (INIS)

Bystritskij, V.M.; Lisitsyn, I.V.; Sinebryukhov, A.A.; Sinebryukhov, V.A.; Kim, A.A.; Kokshenev, V.A.; Koval'chuk, B.M.

1996-01-01

The plasma opening switch (POS) operation at the current level up to 2 MA was studied at the terawatt power GIT-4 generator. The experiments are described in which the electrode diameter and the strength of the applied magnetic field were varied, and different plasma sources were used. It is shown that the high voltage / low impedance switch operation can be achieved if the linear current density at the POS cathode does not exceed 20 kA/cm. This value limits the maximum cathode diameter of the magnetically insulated transmission line. The anode diameter is limited by the requirement of no gap closure with a dense electrode plasma. The application of external magnetic field decreases the plasma density necessary for achieving a long POS conduction time operation regime. (J.U.). 1 tab., 4 refs

Open-Switch Fault Detection Method of a Back-to-Back Converter Using NPC Topology for Wind Turbine Systems

DEFF Research Database (Denmark)

Lee, June-Seok; Lee, Kyo_Beum; Blaabjerg, Frede

2015-01-01

system can break down in the worst case scenario. To improve the reliability of WTG systems, an open-switch fault detection method for back-to-back converters using the NPC topology is required. This study analyzes effects of inner and outer open-switch faults of the NPC rectifier and inverter......In wind turbine generation (WTG) systems, a back-to-back converter with a neutral-point-clamped (NPC) topology is widely used because this topology has more advantages than a conventional two-level topology, particularly when operating at high power. There are 12 switches in the NPC topology....... An open-switch fault in the NPC rectifier of the back-to-back converter leads to the distortion of the input current and torque vibration in the system. Additionally, an open-switch fault in the NPC inverter of the back-to-back converter causes the distortion of the output current. Furthermore, the WTG...

A self-similar model for conduction in the plasma erosion opening switch

International Nuclear Information System (INIS)

Mosher, D.; Grossmann, J.M.; Ottinger, P.F.; Colombant, D.G.

1987-01-01

The conduction phase of the plasma erosion opening switch (PEOS) is characterized by combining a 1-D fluid model for plasma hydrodynamics, Maxwell's equations, and a 2-D electron-orbit analysis. A self-similar approximation for the plasma and field variables permits analytic expressions for their space and time variations to be derived. It is shown that a combination of axial MHD compression and magnetic insulation of high-energy electrons emitted from the switch cathode can control the character of switch conduction. The analysis highlights the need to include additional phenomena for accurate fluid modeling of PEOS conduction

Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses

International Nuclear Information System (INIS)

Agafonov, A.V.; Krastelev, E.G.; Voronin, V.S.

1999-01-01

We present results of experimental research of dynamical properties of thin films of YBa 2 Cu 3 O 7 HTSC-switch models under action of short overcritical current pulses to test this method of control of fast high-power opening switches for accelerator applications

Controlled lid-opening in Thermomyces lanuginosus lipase- An engineered switch for studying lipase function

DEFF Research Database (Denmark)

Skjold-Jørgensen, Jakob; Vind, Jesper; Moroz, Olga V.

2017-01-01

Here, we present a lipase mutant containing a biochemical switch allowing a controlled opening and closing of the lid independent of the environment. The closed form of the TlL mutant shows low binding to hydrophobic surfaces compared to the binding observed after activating the controlled switch...... inducing lid-opening. We directly show that lipid binding of this mutant is connected to an open lid conformation demonstrating the impact of the exposed amino acid residues and their participation in binding at the water-lipid interface. The switch was created by introducing two cysteine residues......-D measurements revealed a seven-fold increase in binding rate for the unlocked lipase. The TlL_locked mutant shows structural changes across the protein important for understanding the mechanism of lid-opening and closing. Our experimental results reveal sites of interest for future mutagenesis studies aimed...

Electron and ion magnetohydrodynamic effects in plasma opening switches

International Nuclear Information System (INIS)

Grossmann, J.M.; DeVore, C.R.; Ottinger, P.F.

1993-01-01

Preliminary results are presented of a numerical code designed to investigate electron and ion magnetohydrodynamic effects in plasma erosion opening switches. The present model is one-dimensional and resolves effects such as the JxB deformation of the plasma, and the penetration of magnetic field either by anomalous resistivity or electron magnetohydrodynamics (Hall effect). Comparisons with exact analytic results and experiment are made

Plasma erosion opening switch in the double-pulse operation mode of a high-current electron accelerator

International Nuclear Information System (INIS)

Isakov, I.F.; Lopatin, V.S.; Remnev, G.E.

1987-01-01

This paper reports the results of investigations of the operation of a fast current opening switch, with a 10/sup 13/-10/sup 16/ plasma density produced either by dielectric surface flashover or by explosive emission of graphite. A series of two pulses was applied to two diodes in parallel. The first pulse produced plasma in the first diode which closed that diode gap by the arrival time of the second pulse. The first, shorted, diode then acted as an erosion switch for the second pulse. A factor of 2.5-3 power multiplication was obtained under optimum conditions. The opening-switch resistance during the magnetic insulation phase, neglecting the electron losses between the switch and the generating diode, exceeded 100 Ω. The duration of the rapid opening phase was less than 5 ns under optimum conditions. This method of plasma production does not require external plasma sources, and permits a wide variation of plasma density, which in turn allows high inductor currents and stored energies

Spectroscopic investigation of species separation in opening switch plasmas

Science.gov (United States)

Jackson, S. L.; Phipps, D. G.; Richardson, A. S.; Commisso, R. J.; Hinshelwood, D. D.; Murphy, D. P.; Schumer, J. W.; Weber, B. V.; Boyer, C. N.; Doron, R.; Biswas, S.; Maron, Y.

2015-11-01

Interactions between magnetic fields and current-carrying plasmas that lead to the separation of plasma species in multi-species plasmas are being studied in a plasma opening switch geometry. Several Marshall guns are used to inject single or multi-species plasmas between coaxial conductors connected to the output of the Naval Research Laboratory's Hawk pulsed-power generator. Following injection of the plasma, the generator is used at roughly half power to apply an electrical pulse with a peak current of 450 kA, a peak voltage of 400 kV, and a rise time of 1.2 μs. The resulting magnetic field interacts with the plasma through a combination of field penetration and magnetohydrodynamic (MHD) pushing that is not well understood but can lead to the separation of plasma species in multi-species plasmas. An ICCD-coupled spectrometer has been used in combination with magnetic probes, a ribbon-beam interferometer, and particle-in-cell (PIC) modeling to diagnose and understand conditions in the plasma from the time it is injected until the end of the conduction phase of the opening switch. This work supported by the Naval Research Laboratory Base Program and the Office of Naval Research.

Explosively formed fuse opening switches for use in flux-compression generator circuits

International Nuclear Information System (INIS)

Goforth, J.H.; Marsh, S.P.

1990-01-01

Explosive-driven magnetic flux compression generators (explosive generators) provide for the generation of large amounts of energy compactly stored in a magnetic field. Opening switches for use in explosive generator circuits allow the energy to be used for applications requiring higher power than can be developed by the generators themselves. The authors have developed a type of opening switch that they describe as an explosively formed fuse (EEF). These switches are well suited to explosive generator circuits and provide a considerable enhancement of explosive pulsed-power capability. The authors first experiments with explosively formed fuses occurred while attempting to utilize the enhanced pressure developed in the high-pressure interaction between two detonation fronts. In these tests they attempted to use the interaction to sever conducting plates along lines perpendicular to current flow. The technique worked to some extent, and to ascertain how much advantage was gained from the high-pressure interaction, they substituted an areal detonation in place of the discrete lines required to produce lines of interaction. This paper describes the authors development effort, the state of the art, and the different manifestations of their technique

Experimental investigation of the ion current distribution in microsecond plasma opening switch

Energy Technology Data Exchange (ETDEWEB)

Bystritskij, V; Grigor` ev, S; Kharlov, A; Sinebryukhov, A [Russian Academy of Sciences, Tomsk (Russian Federation). Institute of Electrophysics

1997-12-31

This paper is devoted to the investigations of properties of the microsecond plasma opening switch (MPOS) as an ion beam source for surface modification. Two plasma sources were investigated: flash-board and cable guns. The detailed measurements of axial and azimuthal distributions of ion current density in the switch were performed. It was found that the azimuthal inhomogeneity of the ion beam increases from the beginning to the end of MPOS. The advantages and problems of this approach are discussed. (author). 5 figs., 2 refs.

Particle-in-cell simulations of plasma opening switch with external magnetic field

International Nuclear Information System (INIS)

Chen Yulan; Zeng Zhengzhong; Sun Fengju

2003-01-01

Fully electromagnetic particle-in-cell simulations are performed to study the effects of an external magnetic field on coaxial plasma opening switch (POS). The simulation results show that POS opening performance can be significantly improved only when external longitudinal magnetic field coils are placed at the cathode side, and an additional azimuthal magnetic field is effective whether the central electrode is of positive or negative polarity. Voltage multiplication coefficient K rises with the additional magnetic field increasing till the electron current is completely magnetically insulated during the opening of POS

A novel carbon gun for use with plasma opening switches

International Nuclear Information System (INIS)

Stevenson, P.; Gregory, K.; Cliffe, R.J.; Smith, I.R.

2001-01-01

The carbon gun is probably the most common plasma source used in plasma opening switches. Nevertheless, it either produces a contaminated plasma, as the flashover surface erodes, or requires regular treatment with graphite paint. The novel form of the plasma gun described in this paper overcomes the disadvantages of existing designs and produces a cleaner plasma. Experimental results illustrate the performance of a prototype system. (author)

Anomalous resistivity in the plasma opening switch

Energy Technology Data Exchange (ETDEWEB)

Dolgachev, G I; Zakatov, L P; Kalinin, Yu G; Kingsep, A S; Nitishinskij, M S; Ushakov, A G [Kurchatov Institute, Moscow (Russian Federation). Applied Physics Division

1997-12-31

Experimental studies and modelling together with analytical considerations of anomalous resistivity in the plasma opening switch (POS) are being pursued to improve the understanding of the physical mechanism of the POS conduction phase. Experiments have been undertaken for a `microsecond` POS of coaxial geometry. Measurements of Stark broadening of the H{sub {alpha}} line allowed turbulent oscillations in plasma to be found at the conductivity stage. A comparison with the modelling including low-frequency (ion-acoustic) turbulence and Doppler broadening (neutral gas temperature 1-3 eV) the electric field value to be estimated to 10-30 kV/cm. The turbulent field increased toward the cathode up to 50 kV/cm in the near-cathode layer. (author). 3 figs., 14 refs.

Diagnosis and Tolerant Strategy of an Open-Switch Fault for T-type Three-Level Inverter Systems

DEFF Research Database (Denmark)

Choi, Uimin; Lee, Kyo Beum; Blaabjerg, Frede

2014-01-01

This paper proposes a new diagnosis method of an open-switch fault and fault-tolerant control strategy for T-type three-level inverter systems. The location of faulty switch can be identified by the average of normalized phase current and the change of the neutral-point voltage. The proposed fault......-tolerant strategy is explained by dividing into two cases: the faulty condition of half-bridge switches and the neutral-point switches. The performance of the T-type inverter system improves considerably by the proposed fault tolerant algorithm when a switch fails. The roposed method does not require additional...... components and complex calculations. Simulation and experimental results verify the feasibility of the proposed fault diagnosis and fault-tolerant control strategy....

Plasma opening switch development for the Particle Beam Fusion Accelerator II (PBFA II)

International Nuclear Information System (INIS)

Stinnett, R.W.; McDaniel, D.H.; Rochau, G.E.

1987-01-01

The authors conducted plasma opening switch (POS) experiments on Sandia National Laboratories' new Particle Beam Fusin Accelerator II (PBFA II) (12 MV, 100 TW, 50 ns), on the Supermite accelerator (2 MV, 2 TW, 50 ns) and on the Naval Research Laboratory's Gamble II accelerator (1.8 MV, 1.6 TW, 70 ns). The POS systems on the PBFA II and Supermite accelerators use a newly developed flashboard plasma source to provide the plasma necessary to conduct the large (> 1 MA) currents produced byu these accelerators. In the Supermite experiments, the plasma opening switch conducted currents up to 1 MA before opening in less than 10 ns into an electron beam load. These experiments achieved significant voltage gain relative to the voltage across a matched load. In experiments on Gamble II, power gains of up to 1.7 were achieved using a POS in a strongly coaxial geometry (r/sub outer//r/sub inner/ = 2) with a large magnetic field at the cathode. The POS system on PBFA II is unique because of its size and voltage. This POS system is designed to conduct over 6 MA before opening. In present experiments it has conducted currents of 4-5 MA for over 50 ns

Enhancing the x-ray output of a single-wire explosion with a gas-puff based plasma opening switch

Science.gov (United States)

Engelbrecht, Joseph T.; Ouart, Nicholas D.; Qi, Niansheng; de Grouchy, Philip W.; Shelkovenko, Tatiana A.; Pikuz, Sergey A.; Banasek, Jacob T.; Potter, William M.; Rocco, Sophia V.; Hammer, David A.; Kusse, Bruce R.; Giuliani, John L.

2018-02-01

We present experiments performed on the 1 MA COBRA generator using a low density, annular, gas-puff z-pinch implosion as an opening switch to rapidly transfer a current pulse into a single metal wire on axis. This gas-puff on axial wire configuration was studied for its promise as an opening switch and as a means of enhancing the x-ray output of the wire. We demonstrate that current can be switched from the gas-puff plasma into the wire, and that the timing of the switch can be controlled by the gas-puff plenum backing pressure. X-ray detector measurements indicate that for low plenum pressure Kr or Xe shots with a copper wire, this configuration can offer a significant enhancement in the peak intensity and temporal distribution of radiation in the 1-10 keV range.

Energetic ion emission in a positive polarity nanosecond plasma opening switch

Energy Technology Data Exchange (ETDEWEB)

Sarfaty, M [Univ. of Wisconsin, Madison, WI (United States); Krasik, Ya E; Weingarten, A; Fruchtman, A; Maron, Y [Weizmann Institute of Science, Rehovot (Israel). Department of Physics

1997-12-31

The emission was studied of energetic ions from the plasma in a coaxial Plasma Opening Switch (POS) powered by a 300 kV, 15 kA, 90 ns positive polarity pulse. Fluxes lasting 2 - 3 ns of ions flowing radially onto the cathode were observed at all axial locations of the switch plasma within 5 ns of the beginning of the upstream POS current. It is suggested that the termination of this ion flux is due to the formation of a cathode plasma, which is consistent with our spectroscopic measurements. Later in the pulse, longer duration (100 ns) ion fluxes were observed radially, first appearing in the generator side of the switch plasma. Fluxes 30 - 40 ns long of ions flowing axially towards the POS load at velocities (2{+-}1) x 10{sup 8} cm/s were also observed. The dependences of the start time of the axial ion flow, of the ion velocities, and of the ion flux on the POS operation parameters were studied. (author). 6 figs., 5 refs.

Energetic ion emission in a positive polarity nanosecond plasma opening switch

International Nuclear Information System (INIS)

Sarfaty, M.; Krasik, Ya.E.; Weingarten, A.; Fruchtman, A.; Maron, Y.

1996-01-01

The emission was studied of energetic ions from the plasma in a coaxial Plasma Opening Switch (POS) powered by a 300 kV, 15 kA, 90 ns positive polarity pulse. Fluxes lasting 2 - 3 ns of ions flowing radially onto the cathode were observed at all axial locations of the switch plasma within 5 ns of the beginning of the upstream POS current. It is suggested that the termination of this ion flux is due to the formation of a cathode plasma, which is consistent with our spectroscopic measurements. Later in the pulse, longer duration (100 ns) ion fluxes were observed radially, first appearing in the generator side of the switch plasma. Fluxes 30 - 40 ns long of ions flowing axially towards the POS load at velocities (2±1) x 10 8 cm/s were also observed. The dependences of the start time of the axial ion flow, of the ion velocities, and of the ion flux on the POS operation parameters were studied. (author). 6 figs., 5 refs

Diagnosis method of an open-switch fault for a grid-connected T-type three-level inverter system

DEFF Research Database (Denmark)

Choi, U. M.; Lee, K. B.; Blaabjerg, Frede

2012-01-01

-tolerant control algorithm can be used when the open switch fault occurs in the middle switches. It is achieved by simply modifying the conventional SVM method. The proposed methods are advantageous as they do not require additional sensors and they do not involve complex calculations. Therefore, this method...

Two-dimensional single fluid MHD simulations of plasma opening switches

International Nuclear Information System (INIS)

Roderick, N.F.; Payne, S.S.; Peterkin, R.E. Jr.; Frese, M.H.; Hussey, T.W.

1989-01-01

Simulations of plasma opening switch have been made using two-dimensional, single fluid, magnetohydrodynamic codes HAM and MACH2. A variety of mechanisms for magnetic field penetration have been investigated. These include plasma convection, classical and microturbulent resistive diffusion, and Hall effect transport. We find that plasma microturbulent models are necessary to explain the broad current channels observed in experiments. Both heuristic and consistent microturbulent models are able to explain observed channel widths and penetration features. The best results are obtained for a consistent model that includes the Buneman, ion acoustic, and lower hybrid microturbulent collision frequencies and threshold conditions. Maximum microturbulent collision frequencies of 5 ω p , are typical. Field transport and current channel profiles are in excellent agreement with experimental observations for GAMBLE I, GAMBLE II, and SUPERMITE experiments. Dominant field penetration mechanisms and center of mass plasma motion are current and density dependent. Including the Hall effect enhanced field penetration. Center of mass motion is negligible for the GAMBLE I experiments but significant for the GAMBLE II conditions. Scaling of plasma opening time with switch length and density can be fit by linear representations for lengths from 0.03 m to 0.24 m and ion densities from 10 18 m -3 to 1.5 times 10 19 m -3 . 15 refs., 7 figs., 1 tab

Plasma opening switch studies of the applied Bz diode on the LION accelerator

International Nuclear Information System (INIS)

Struckman, C.K.; Kusse, B.R.; Meyerhofer, D.D.; Rondeau, G.

1988-01-01

The LION accelerator, 1.5 MV, 4Ω, at Cornell University is being used to study the characteristics of an applied B z , or, barrel diode. A plasma opening switch (POS) has been used to shape the voltage pulse seen by the diode. The results of a series of experiments utilizing a POS are presented. The plasma switch geometry is unique, with the plasma source located inside the center conductor of a coaxial transmission line. The switch region is located between the 17 cm radius anode and the 23 cm radius cathode. The switch is constructed of a flashboard plasma source bent into an azimuthally symmetric ring. The axial length of the plasma is only about 2 cm; which is much smaller than the switch radius. The plasma diffuses into the anode-cathode space through axially oriented slots in the anode. The plasma in the switch region has been characterized during static testing (no generator pulse) using Faraday cups. By using time of flight calculations, the Faraday cups give rough estimates of both the plasma density and velocity. Since the generator pulse is so short (100 ns) these static characterizations are indicative of the plasma when the voltage pulse is present. This low density, fast plasma produced the best results for the diode voltage pulse. Results from recently constructed Langmuir probes are also presented

Analytical Performance Evaluation of Different Switch Solutions

Directory of Open Access Journals (Sweden)

Francisco Sans

2013-01-01

Full Text Available The virtualization of the network access layer has opened new doors in how we perceive networks. With this virtualization of the network, it is possible to transform a regular PC with several network interface cards into a switch. PC-based switches are becoming an alternative to off-the-shelf switches, since they are cheaper. For this reason, it is important to evaluate the performance of PC-based switches. In this paper, we present a performance evaluation of two PC-based switches, using Open vSwitch and LiSA, and compare their performance with an off-the-shelf Cisco switch. The RTT, throughput, and fairness for UDP are measured for both Ethernet and Fast Ethernet technologies. From this research, we can conclude that the Cisco switch presents the best performance, and both PC-based switches have similar performance. Between Open vSwitch and LiSA, Open vSwitch represents a better choice since it has more features and is currently actively developed.

Limiting parameters of the plasma opening switch

International Nuclear Information System (INIS)

Dolgachev, G.I.; Ushakov, A.G.

2001-01-01

Implementing programs for nuclear fusion research and X-ray generation requires the creation of superpower generators based on plasma opening switches (POSs) capable of commutating currents as high as several tens of megaamperes at output voltages of up to 5 MV and higher. The physical mechanisms limiting the POS voltage are investigated. It is shown that, as the generator voltage U g increases, the voltage multiplication factor k U POS /U g (where U POS is the POS voltage) decreases. An explanation for such a dependence is proposed, and the maximum value of the POS voltage is estimated. A POS design that enables operating in the above current and voltage ranges is considered. The design is based on applying an external magnetic field to the POS interelectrode gap, increasing the initial generator voltage, and decreasing the linear (along the perimeter of the outer electrode) density of the charge passing through the POS during the conduction phase

Preliminary studies of the plasma focus as an opening switch

International Nuclear Information System (INIS)

Venneri, F.; Gerdin, G.

1983-01-01

Sharp current interruption at pinch time suggests the possible application of the plasma focus as an opening switch. Switch impedances on the order of 0.5 ohms or greater would be of interest to pulsed power applications if the rise time for the impedance is sufficiently short. The experimental determination of the magnitude of the plasma focus impedance at pinch time and its nature (R or L) are obviously important in assessing the feasibility of this application. An experimental estimate of the Spitzer resistance of the plasma focus based on soft-X-ray measurements indicates a Spitzer resistance of 9 mΩ. Estimates of resistance based on the maximum particle energy observed 4 (V about E /sub MAX/ /e) and the current at pinch time (R about E /sub MAX/ /eI /sub p/ ) would indicate an effective resistance of about one ohm. Estimates of resistance based on circuit parameters (L, I, q/C) yield about one third of an ohm. To resolve these discrepancies a exclamationBexclamation probe 5 is being developed to get a better estimate of L(t), L(t) and I(t) through spatially resolved measurements. Preliminary results are reported

Recent progress in Open Data production and consumption - examples from a Governmental institute (SMHI) and a collaborative EU research project (SWITCH-ON)

Science.gov (United States)

Arheimer, Berit; Falkenroth, Esa

2014-05-01

The Swedish Meteorological and Hydrological Institute (SMHI) has a long tradition both in producing and consuming open data on a national, European and global scale. It is also promoting community building among water scientists in Europe by participating in and initiating collaborative projects. This presentation will exemplify the contemporary European movement imposed by the INSPIRE directive and the Open Data Strategy, by showing the progress in openness and shift in attitudes during the last decade when handling Research Data and Public Sector Information at a national European institute. Moreover, the presentation will inform about a recently started collaborative project (EU FP7 project No 603587) coordinated by SMHI and called SWITCH-ON http://water-switch-on.eu/. The project addresses water concerns and currently untapped potential of open data for improved water management across the EU. The overall goal of the project is to make use of open data, and add value to society by repurposing and refining data from various sources. SWITCH-ON will establish new forms of water research and facilitate the development of new products and services based on principles of sharing and community building in the water society. The SWITCH-ON objectives are to use open data for implementing: 1) an innovative spatial information platform with open data tailored for direct water assessments, 2) an entirely new form of collaborative research for water-related sciences, 3) fourteen new operational products and services dedicated to appointed end-users, 4) new business and knowledge to inform individual and collective decisions in line with the Europe's smart growth and environmental objectives. The presentation will discuss challenges, progress and opportunities with the open data strategy, based on the experiences from working both at a Governmental institute and being part of the global research community.

Open-loop correction for an eddy current dominated beam-switching magnet.

Science.gov (United States)

Koseki, K; Nakayama, H; Tawada, M

2014-04-01

A beam-switching magnet and the pulsed power supply it requires have been developed for the Japan Proton Accelerator Research Complex. To switch bunched proton beams, the dipole magnetic field must reach its maximum value within 40 ms. In addition, the field flatness should be less than 5 × 10(-4) to guide each bunched beam to the designed orbit. From a magnetic field measurement by using a long search coil, it was found that an eddy current in the thick endplates and laminated core disturbs the rise of the magnetic field. The eddy current also deteriorates the field flatness over the required flat-top period. The measured field flatness was 5 × 10(-3). By using a double-exponential equation to approximate the measured magnetic field, a compensation pattern for the eddy current was calculated. The integrated magnetic field was measured while using the newly developed open-loop compensation system. A field flatness of less than 5 × 10(-4), which is an acceptable value, was achieved.

Observation of plasma motion in a coaxial plasma opening switch with a chordal laser interferometer

International Nuclear Information System (INIS)

Teramoto, Y.; Urakami, H.; Akiyama, H.; Kohno, S.; Katsuki, S.

2002-01-01

Electron densities in a coaxial plasma opening switch were measured at many lines-of-slight. In the present experiment, electron density was measured by a He-Ne laser interferometer with chordal lines-of sight. In order to observe the motion of the POS plasma, the electron density contours during the conduction, opening and post-opening phases were drawn by combining the results of interferometer experiments. The radial and axial motion of POS plasma was investigated from the density contours. As conduction time progressed, the POS plasma moved toward downstream. At 800 ns, which corresponds to the time of opening in the current waveform, low-density region less than 10 15 cm -2 is seen at 10 mm from the cathode. After the opening was completed, the low-density gap disappeared and the shape of the corn-shape-like plasma was distorted. (author)

An open-closed-loop iterative learning control approach for nonlinear switched systems with application to freeway traffic control

Science.gov (United States)

Sun, Shu-Ting; Li, Xiao-Dong; Zhong, Ren-Xin

2017-10-01

For nonlinear switched discrete-time systems with input constraints, this paper presents an open-closed-loop iterative learning control (ILC) approach, which includes a feedforward ILC part and a feedback control part. Under a given switching rule, the mathematical induction is used to prove the convergence of ILC tracking error in each subsystem. It is demonstrated that the convergence of ILC tracking error is dependent on the feedforward control gain, but the feedback control can speed up the convergence process of ILC by a suitable selection of feedback control gain. A switched freeway traffic system is used to illustrate the effectiveness of the proposed ILC law.

OpenFlow Switching Performance using Network Simulator - 3

OpenAIRE

Sriram Prashanth, Naguru

2016-01-01

Context. In the present network inventive world, there is a quick expansion of switches and protocols, which are used to cope up with the increase in customer requirement in the networking. With increasing demand for higher bandwidths and lower latency and to meet these requirements new network paths are introduced. To reduce network load in present switching network, development of new innovative switching is required. These required results can be achieved by Software Define Network or Trad...

Transient-Switch-Signal Suppressor

Science.gov (United States)

Bozeman, Richard J., Jr.

1995-01-01

Circuit delays transmission of switch-opening or switch-closing signal until after preset suppression time. Used to prevent transmission of undesired momentary switch signal. Basic mode of operation simple. Beginning of switch signal initiates timing sequence. If switch signal persists after preset suppression time, circuit transmits switch signal to external circuitry. If switch signal no longer present after suppression time, switch signal deemed transient, and circuit does not pass signal on to external circuitry, as though no transient switch signal. Suppression time preset at value large enough to allow for damping of underlying pressure wave or other mechanical transient.

Study of the switching rate of gas-discharge devices based on the open discharge with counter-propagating electron beams

International Nuclear Information System (INIS)

Bokhan, P. A.; Gugin, P. P.; Lavrukhin, M. A.; Zakrevsky, Dm. E.

2015-01-01

The switching rate of gas-discharge devices “kivotrons” based on the open discharge with counter-propagating electron beams has been experimentally studied. Structures with 2-cm 2 overall cathode area were examined. The switching time was found to show a monotonic decrease with increasing the working-gas helium pressure and with increasing the voltage across the discharge gap at breakdown. The minimum switching time was found to be ∼240 ps at 17 kV voltage, and the maximum rate of electric-current rise limited by the discharge-circuit inductance was 3 × 10 12  A/s

Experimental investigation of the material surface modification in microsecond plasma opening switch

Energy Technology Data Exchange (ETDEWEB)

Bystritskij, V; Grigor` ev, S; Kharlov, A; Sinebryukhov, A [Russian Academy of Sciences, Tomsk (Russian Federation). Institute of Electrophysics; Burkov, P [Russian Academy of Scinces, Tomsk (Russian Federation). Institute of Strength Physics and Materials Control; Grigorev, V; Koval, T [Institute of Nuclear Physics, Tomsk (Russian Federation)

1997-12-31

The paper is devoted to the investigations of the material surface modification by high power ion beam generated in microsecond plasma opening switch (MPOS). Various types of steels were investigated: stainless steel 17-4PH, carbon steel C1020, pure iron. For all these materials, the optimal regimes for irradiation were defined. A significant increase in microhardness (1.5 to 2-fold) was obtained for these materials. Numerical calculations and theoretical estimations of the ion beam-matter interaction were also performed. The advantages and problems of this approach are discussed. (author). 8 figs., 3 refs.

Observation of plasma motion in a coaxial plasma opening switch with a chordal laser interferometer

Energy Technology Data Exchange (ETDEWEB)

Teramoto, Y.; Urakami, H.; Akiyama, H. [Kumamoto Univ., Graduate School of Science and Technology, Kumamoto (Japan); Kohno, S. [Ariake National College of Technology, Dept. of Electrical Engineering, Fukuoka (Japan); Katsuki, S. [Kumamoto Univ., Dept. of Electrical and Computer Engineering, Kumamoto (Japan)

2002-06-01

Electron densities in a coaxial plasma opening switch were measured at many lines-of-slight. In the present experiment, electron density was measured by a He-Ne laser interferometer with chordal lines-of sight. In order to observe the motion of the POS plasma, the electron density contours during the conduction, opening and post-opening phases were drawn by combining the results of interferometer experiments. The radial and axial motion of POS plasma was investigated from the density contours. As conduction time progressed, the POS plasma moved toward downstream. At 800 ns, which corresponds to the time of opening in the current waveform, low-density region less than 10{sup 15} cm{sup -2} is seen at 10 mm from the cathode. After the opening was completed, the low-density gap disappeared and the shape of the corn-shape-like plasma was distorted. (author)

Time resolved plasma characterization in a long conduction time planar plasma opening switch

International Nuclear Information System (INIS)

Adler, L.K.; Greenly, J.B.; Qi, N.; Hammer, D.A.

1989-01-01

The authors discuss additional experiments in which the plasma dynamics and properties will be monitored in detail before and during opening. Space and time resolved density, temperature and motion information about the plasma and neutrals is given by emission spectroscopy and streak photography and correlated to the current and voltage traces. Specifically, we will look for the effects of neutrals evolving off of surfaces, stagnation of the switch plasma, and rvec J x rvec B motion of the plasma downstream of the switch. Diagnostics include current and voltage monitors, a multi-aperture biased Faraday cup, emission spectroscopy and streak photography. Pairs of B dot loops are positioned in the stripline just upstream and downstream of the POS. Also, two single B loops were placed further downstream to look for bulk plasma motion. An inductive monitor gives the voltage at the upstream side of the POS and the Faraday cup monitors the gun plasma consistency from shot to shot

Mega-Amp Opening Switch with Nested Electrodes/Pulsed Generator of Ion and Ion Cluster Beams.

Science.gov (United States)

1985-07-01

i.e., noncollisiona].) resistivity which controls the "~switch opening" function (specifically, the rate of disintergration of the PF pinch where...unaffected the pinch field Be and then disassemble in a light (D) component and other heavy components. Production and propagation of-neutrals (from...emission, production and - evaporation would imply a distorsion of the pinholeimage-because of B -which is not p.-.. observed (our pinhole resolution is 150

Investigation of electron and ion flows in the microsecond plasma opening switch on the terawatt power level

International Nuclear Information System (INIS)

Bastrikov, A.N.; Bugaev, S.P.; Volkov, A.M.; Kim, A.A.; Kovalchuk, B.M.; Kokshener, V.M.; Yakovlev, V.A.; Bystritskii, V.M.; Grigoriev, S.V.; Krasik, Ya.E.

1989-01-01

The results of an investigation of ion and electron flows in the coaxial microsecond plasma opening switch (POS) at generator GIT-4 are given. The 1 mks front duration POS with outer and inner electrodes of 210 mm and 75 mm diameters respectively switched 1 MA pulse during 0.1 mks to the short circuited coaxial line with the same diameters and 120 cm of length. The polarity of the inner electrode was negative. The plasma of the POS was injected from outer electrode by 32 plasma guns of capillary type. The typical POS voltage was 0.9-1.2 MV. The calculated energy losses in the POS during the switching phase reached (0.1-0.15) MJ. The calorimetric measurements of the energy dissipated on both electrodes gave the same value. The location and distribution of the head absorbed along the POS electrodes were determined

Operation of a semiconductor opening switch at ultrahigh current densities

International Nuclear Information System (INIS)

Lyubutin, S. K.; Rukin, S. N.; Slovikovsky, B. G.; Tsyranov, S. N.

2012-01-01

The operation of a semiconductor opening switch (SOS diode) at cutoff current densities of tens of kA/cm 2 is studied. In experiments, the maximum reverse current density reached 43 kA/cm 2 for ∼40 ns. Experimental data on SOS diodes with a p + -p-n-n + structure and a p-n junction depth from 145 to 180 μm are presented. The dynamics of electron-hole plasma in the diode at pumping and current cutoff stages is studied by numerical simulation methods. It is shown that current cutoff is associated with the formation of an electric field region in a thin (∼45 μm) layer of the structure’s heavily doped p-region, in which the acceptor concentration exceeds 10 16 cm −3 , and the current cutoff process depends weakly on the p-n junction depth.

Coupling between feedback loops in autoregulatory networks affects bistability range, open-loop gain and switching times

International Nuclear Information System (INIS)

Tiwari, Abhinav; Igoshin, Oleg A

2012-01-01

Biochemical regulatory networks governing diverse cellular processes such as stress-response, differentiation and cell cycle often contain coupled feedback loops. We aim at understanding how features of feedback architecture, such as the number of loops, the sign of the loops and the type of their coupling, affect network dynamical performance. Specifically, we investigate how bistability range, maximum open-loop gain and switching times of a network with transcriptional positive feedback are affected by additive or multiplicative coupling with another positive- or negative-feedback loop. We show that a network's bistability range is positively correlated with its maximum open-loop gain and that both quantities depend on the sign of the feedback loops and the type of feedback coupling. Moreover, we find that the addition of positive feedback could decrease the bistability range if we control the basal level in the signal-response curves of the two systems. Furthermore, the addition of negative feedback has the capacity to increase the bistability range if its dissociation constant is much lower than that of the positive feedback. We also find that the addition of a positive feedback to a bistable network increases the robustness of its bistability range, whereas the addition of a negative feedback decreases it. Finally, we show that the switching time for a transition from a high to a low steady state increases with the effective fold change in gene regulation. In summary, we show that the effect of coupled feedback loops on the bistability range and switching times depends on the underlying mechanistic details. (paper)

Switched-based interference reduction scheme for open-access overlaid cellular networks

KAUST Repository

Radaydeh, Redha Mahmoud Mesleh

2012-06-01

Femtocells have been proposed to enhance the spatial coverage and system capacity of existing cellular networks. However, this technology may result in significant performance loss due to the increase in co-channel interference, particularly when coordination between access points is infeasible. This paper targets interference management in such overlaid networks. It is assumed that the femtocells employ the open-access strategy to reduce cross-tier interference, and can share resources concurrently. It is also assumed that each end user (EU) can access one channel at a time, and transfer limited feedback. To reduce the effect of co-tier interference in the absence of the desired EU channel state information (CSI) at the serving access point as well as coordination between active access points, a switched scheme based on the interference levels associated with available channels is proposed. Through the analysis, the scheme modes of operation in under-loaded and over-loaded channels are studied, from which the statistics of the resulting interference power are quantified. The impact of the proposed scheme on the received desired power is thoroughly discussed. In addition, the effect of the switching threshold on the achieved performance of the desired EU is investigated. The results clarify that the proposed scheme can improve the performance while reducing the number of examined channels and feedback load. © 2012 IEEE.

Uji Performa Software-based Openflow Switch Berbasis Openwrt

OpenAIRE

Kartadie, Rikie; Suryanto, Tommy

2015-01-01

Perkembangan pesat Software-Defined Network telah dirasakan oleh vendor vendor besar. HP, Google dan IBM, mulai merubah pola routing-switching pada network mereka dari pola routingswitching tradisional ke pola infrastruktur routing-switching Software-defined Network. Untuk melakukan eksperimen tentang OpenFlow, para peneliti sering kali harus menggunakan perangkat hardware/dedicated switch OpenFlow yang dikeluarkan oleh beberapa vendor dengan harga yang tinggi. Kenyataannya, software-based sw...

Magnetic field propagation in a two ion species planar plasma opening switch

International Nuclear Information System (INIS)

Strauss, H. R.; Doron, R.; Arad, R.; Rubinstein, B.; Maron, Y.; Fruchtman, A.

2007-01-01

Three fluid plasma evolution equations are applied to the problem of magnetic field propagation in a planar plasma opening switch. For certain initial conditions in which Hall parameter H∼1, magnetic field penetration due to the Hall field, initially, as expected, either opposes or adds to the hydromagnetic pushing, depending on the polarity of the magnetic field relative to the density gradient. Later, however, the plasma pushing by the magnetic field is found in the case studied here to modify the plasma density in a way that the density gradient tends to align with the magnetic field gradient, effectively turning off the Hall effect. The penetration of the magnetic field then ceases and plasma pushing becomes the dominant process

Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch.

Science.gov (United States)

Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

2016-01-19

Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture.

Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch

Directory of Open Access Journals (Sweden)

Tao Huang

2016-01-01

Full Text Available Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture.

Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch

Science.gov (United States)

Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

2016-01-01

Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture. PMID:26797616

Software Switching for Data Acquisition

CERN Multimedia

CERN. Geneva; Malone, David

2016-01-01

In this talk we discuss the feasibility of replacing telecom-class routers with a topology of commodity servers acting as software switches in data acquisition. We extend the popular software switch, Open vSwitch, with a dedicated, throughput-oriented buffering mechanism. We compare the performance under heavy many-to-one congestion to typical Ethernet switches and evaluate the scalability when building larger topologies, exploiting the integration with software-defined networking technologies. Please note that David Malone will speak on behalf of Grzegorz Jereczek.

Plasma density evolution in plasma opening switch obtained by a time-resolved sensitive He-Ne interferometer

Science.gov (United States)

Chen, Lin; Ren, Jing; Guo, Fan; Zhou, LiangJi; Li, Ye; He, An; Jiang, Wei

2014-03-01

To understand the formation process of vacuum gap in coaxial microsecond conduction time plasma opening switch (POS), we have made measurements of the line-integrated plasma density during switch operation using a time-resolved sensitive He-Ne interferometer. The conduction current and conduction time in experiments are about 120 kA and 1 μs, respectively. As a result, more than 85% of conduction current has been transferred to an inductive load with rise time of 130 ns. The radial dependence of the density is measured by changing the radial location of the line-of-sight for shots with the same nominal POS parameters. During the conduction phase, the line-integrated plasma density in POS increases at all radial locations over the gun-only case by further ionization of material injected from the guns. The current conduction is observed to cause a radial redistribution of the switch plasma. A vacuum gap forms rapidly in the plasma at 5.5 mm from the center conductor, which is consistent with the location where magnetic pressure is the largest, allowing current to be transferred from the POS to the load.

Performance Test of Openflow Agent on Openflow Software-Based Mikrotik RB750 Switch

Directory of Open Access Journals (Sweden)

Rikie Kartadie

2016-11-01

Full Text Available A network is usually developed by several devices such as router, switch etc. Every device forwards data package manipulation with complicated protocol planted in its hardware. An operator is responsible for running configuration either to manage rules or application applied in the network. Human error may occur when device configuration run manually by operator. Some famous vendors, one of them is MikroTik, has also been implementing this OpenFlow on its operation. It provides the implementation of SDN/OpenFlow architecture with affordable cost. The second phase research result showed that switch OF software-based MikroTik resulted higher latency value than both mininet and switch OF software-based OpenWRT. The average gap value of switch OF software-based MikroTik is 2012 kbps lower than the value of switch OF software-based OpenWRT. The average gap value of throughput bandwidth protocol UDP switch OF software-based MikroTik is 3.6176 kBps lower than switch OF software-based OpenWRT and it is 8.68 kBps lower than mininet. The average gap throughput jitter protokol UDP of switch OF software-based MiktoTik is 0.0103ms lower than switch OF software-based OpenWRT and 0.0093ms lower than mininet. 

An Enhanced Three-Level Voltage Switching State Scheme for Direct Torque Controlled Open End Winding Induction Motor

Science.gov (United States)

Kunisetti, V. Praveen Kumar; Thippiripati, Vinay Kumar

2018-01-01

Open End Winding Induction Motors (OEWIM) are popular for electric vehicles, ship propulsion applications due to less DC link voltage. Electric vehicles, ship propulsions require ripple free torque. In this article, an enhanced three-level voltage switching state scheme for direct torque controlled OEWIM drive is implemented to reduce torque and flux ripples. The limitations of conventional Direct Torque Control (DTC) are: possible problems during low speeds and starting, it operates with variable switching frequency due to hysteresis controllers and produces higher torque and flux ripple. The proposed DTC scheme can abate the problems of conventional DTC with an enhanced voltage switching state scheme. The three-level inversion was obtained by operating inverters with equal DC-link voltages and it produces 18 voltage space vectors. These 18 vectors are divided into low and high frequencies of operation based on rotor speed. The hardware results prove the validity of proposed DTC scheme during steady-state and transients. From simulation and experimental results, proposed DTC scheme gives less torque and flux ripples on comparison to two-level DTC. The proposed DTC is implemented using dSPACE DS-1104 control board interface with MATLAB/SIMULINK-RTI model.

The Energy Balance of Plasma in a Coaxial Plasma Opening Switch

International Nuclear Information System (INIS)

Xu Xiang; Wang Younian

2006-01-01

The two-dimensional energy balance in a coaxial plasma opening switch (POS) is studied based on the single-fluid magnetohydrodynamic (MHD) equations coupled with the generalized Ohm's law. The energy transfers between the plasma and the magnetic field are considered during the penetration of the magnetic field as the Ohmic heating is included in the energy-balance equation. The focus is on the energy partition between the magnetic-field energy and the dissipated magnetic-field energy in a high-density POS with different rise-in-time electric currents at the generator boundary. The simulation code is tested in two cases: the constant-in-time current case and the linear rise-in-time current case. For the sinusoidally rise-in-time current similar to that of the experiments, it is shown that at the end of the conduction phase the dissipated magnetic-field energy is 36.5% of the input electromagnetic energy, which is consistent with the experimental results

RS-20 type repetitive generator with planar configuration of plasma opening switch

Energy Technology Data Exchange (ETDEWEB)

Agalakov, V P; Barinov, N U; Belenki, G S [Kurchatov Inst., Moscow (Russian Federation); and others

1997-12-31

The existing experience with the production of repetitive rate accelerators with a high peak power (in excess of 10{sup 10} W) and an average power above 50 kW makes it possible to resolve a number of physics and technology tasks which are connected with the reliability and life of the accelerator. The design and results on optimization of a simple plasma opening switch (POS) are discussed. The final design of the POS provided voltages of up to 2 MV and had a life of more than 105 pulses including 4 hours of continuous operation under 4 Hz repetition rate and wall plug power 65 kW. This unit was tested at the RS-20 type accelerator both at the Kurchatov Institute and at the Northwest Institute of Nuclear Technology in China. (author). 5 figs., 1 ref.

The Aurora accelerator's triggered oil switch

International Nuclear Information System (INIS)

Weidenheimer, D.M.; Pereira, N.R.; Judy, D.C.; Stricklett, K.L.

1993-01-01

Achieving a radiation pulse with 15 ns risetime using all four of the Aurora accelerator's Blumlein pulse-forming lines demands synchronization of the Blumleins to within 10 ns (in addition to a 15 ns risetime for a single line). Timing of each Blumlein is controlled by a triggered 12 MV oil switch. A smaller-than-customary trigger electrode makes the switching time more reproducible. Time-resolved photography of the oil arcs suggests that triggering occurs simultaneously around the sharp edge of the trigger electrode, perhaps with small deviations that grow into the most prominent arcs characteristically seen in open-shutter photographs. However, many smaller arcs that are usually overlooked in open-shutter pictures may contribute to current conduction in a closed switch

Subnanosecond linear GaAs photoconductive switching, revision 1

Science.gov (United States)

Druce, R. L.; Pocha, M. D.; Griffin, K. L.; Hofer, W. W.

Research was conducted in photoconductive switching for the purpose of generating subnanosecond pulses in the 25 to 50kV range. The very fast recombination rates of Gallium Arsenide (GaAs) was exploited to explore the potential of GaAs as a closing and opening switch when operating in the linear mode (the linear mode is defined such that one carrier pair is generated for each photon absorbed). The closing time of a linear GaAs switch is theoretically limited by the characteristics of the laser pulse used to activate the switch (the carrier generation time in GaAs is (approx. 10(-14) sec) while the opening time is theoretically limited by the recombination time of the carriers. The recombination time is several ns for commercially available semi-insulating GaAs. Doping or neutron irradiation can reduce the recombination time to less than 100 ps. Switch closing times of less than 200 ps with a 100 ps duration laser pulse and opening times of less than 400 ps with neutron irradiated GaAs at fields of tens of kV/cm was observed. The illumination source was a Nd:YAG laser operating at 1.06 microns.

Electrochemical Switching of Conductance with Diarylethene-Based Redox-Active Polymers

DEFF Research Database (Denmark)

Logtenberg, Hella; van der Velde, Jasper H. M.; de Mendoza, Paula

2012-01-01

Reversible switching of conductance using redox triggered switching of a polymer-modified electrode is demonstrated. A bifunctional monomer comprising a central electroswitchable core and two bithiophene units enables formation of a film through anodic electropolymerization. The conductivity...... of the polymer can be switched electrochemically in a reversible manner by redox triggered opening and closing of the diarylethene unit. In the closed state, the conductivity of the modified electrode is higher than in the open state....

Study of electron and ion fluxes in a microsecond plasma switch during current switch phase at power level of 0,2TW

International Nuclear Information System (INIS)

Anan'in, P.S.; Bystritskij, V.M.; Karpov, V.B.; Krasik, Ya.E.; Lisitsin, I.V.; Sinebryukhov, A.A.

1991-01-01

Results of experimental study of dynamics of electron and ion losses in a microsecond plasma switch (PS), carring the short-circuited inductance load and operating with open potential electrode, are presented. Investigations were carried out at 'DUBL' microsecond generator with stored energy of 56 kJ and 300 kA current amplitude in inductive storage. The investigations showed that primary channel of energy losses, limiting microsecond plasma switch impedance, are energy losses: they constitute 70% of all losses under inductive load and 30% during operation with an open cathode. It was shown that ion current in PS attains its peak value by the end of conductivity phase and it does not increase in switch phase. With an open cathode, PS impedance is defined by an electron beam, forming during current switch phase and propagating towards external electrode end. In this high-current electron beam H + ions, accelerated up to 3.5-4.2 MeV energy, and outcoming from PS plasma boundary, were detected

Electron collisions in gas switches

International Nuclear Information System (INIS)

Christophorou, L.G.

1989-01-01

Many technologies rely on the conduction/insulation properties of gaseous matter for their successful operation. Many others (e.g., pulsed power technologies) rely on the rapid change (switching or modulation) of the properties of gaseous matter from an insulator to a conductor and vice versa. Studies of electron collision processes in gases aided the development of pulsed power gas switches, and in this paper we shall briefly illustrate the kind of knowledge on electron collision processes which is needed to optimize the performance of such switching devices. To this end, we shall refer to three types of gas switches: spark gap closing, self-sustained diffuse discharge closing, and externally-sustained diffuse discharge opening. 24 refs., 15 figs., 2 tabs

Beginning Microsoft Visual Studio LightSwitch Development

CERN Document Server

Novák, István

2011-01-01

Learn how LightSwitch can accelerate and simplify application development As Microsoft's newest offering for simplifying application development, LightSwitch opens the development door to creating applications without writing code. This introductory, full-color book shows you how to quickly create, modify, and distribute information for your business with LightSwitch. Packed with simple example programs, this beginner-level resource guides you through a complete small business application using LightSwitch to demonstrate the capabilities of this exciting new tool. You'll explore the most commo

Subnanosecond linear GaAs photoconductive switching: Revision 1

Energy Technology Data Exchange (ETDEWEB)

Druce, R.L.; Pocha, M.D.; Griffin, K.L.; Hofer, W.W.

1989-01-01

We are conducting research in photoconductive switching for the purpose of generating subnanosecond pulses in the 25--50kV range. We are exploiting the very fast recombination rates of Gallium Arsenide (GaAs) to explore the potential of GaAs as a closing and opening switch when operating in the linear mode (the linear mode is defined such that one carrier pair is generated for each photon absorbed). The closing time of a linear GaAs switch is theoretically limited by the characteristics of the laser pulse used to activate the switch (the carrier generation time in GaAs is /approximately/10/sup /minus/14/ sec) while the opening time is theoretically limited by the recombination time of the carriers. The recombination time is several ns for commercially available semi-insulating GaAs. Doping or neutron irradiation can reduce the recombination time to less than 100 ps. We have observed switch closing times of less than 200 ps with a 100 ps duration laser pulse and opening times of less than 400 ps with neutron irradiated GaAs at fields of tens of kV/cm. The illumination source was a Nd:YAG laser operating at 1.06 /mu/m. 4 refs., 11 figs.

Dynamics of the plasma injected into the gap of a plasma opening switch across a strong magnetic field

International Nuclear Information System (INIS)

Dolgachev, G. I.; Maslennikov, D. D.; Ushakov, A. G.; Fedotkin, A. S.; Khodeev, I. A.; Shvedov, A. A.

2011-01-01

A method is proposed to increase the linear charge density transferred through a plasma opening switch (POS) and, accordingly, reduce the POS diameter by enhancing the external magnetic field in the POS gap. Results are presented from experimental studies of the dynamics of the plasma injected into the POS gap across a strong magnetic field. The possibility of closing the POS gap by the plasma injected across an external magnetic field of up to 60 kG is demonstrated.

Gap formation processes in a high-density plasma opening switch

International Nuclear Information System (INIS)

Grossmann, J.M.; Swanekamp, S.B.; Ottinger, P.F.; Commisso, R.J.; Hinshelwood, D.D.; Weber, B.V.

1995-01-01

A gap opening process in plasma opening switches (POS) is examined with the aid of numerical simulations. In these simulations, a high density (n e =10 14 --5x10 15 cm -3 ) uniform plasma initially bridges a small section of the coaxial transmission line of an inductive energy storage generator. A short section of vacuum transmission line connects the POS to a short circuit load. The results presented here extend previous simulations in the n e =10 12 --10 13 cm -3 density regime. The simulations show that a two-dimensional (2-D) sheath forms in the plasma near a cathode. This sheath is positively charged, and electrostatic sheath potentials that are large compared to the anode--cathode voltage develop. Initially, the 2-D sheath is located at the generator edge of the plasma. As ions are accelerated out of the sheath, it retains its original 2-D structure, but migrates axially toward the load creating a magnetically insulated gap in its wake. When the sheath reaches the load edge of the POS, the POS stops conducting current and the load current increases rapidly. At the end of the conduction phase a gap exists in the POS whose size is determined by the radial dimensions of the 2-D sheath. Simulations at various plasma densities and current levels show that the radial size of the gap scales roughly as B/n e , where B is the magnetic field. The results of this work are discussed in the context of long-conduction-time POS physics, but exhibit the same physical gap formation mechanisms as earlier lower density simulations more relevant to short-conduction-time POS. copyright 1995 American Institute of Physics

High voltage disconnect switch position monitoring

Energy Technology Data Exchange (ETDEWEB)

Crampton, S W

1983-08-01

Unreliable position indication on high-voltage (HV) disconnect switches can result in equipment damage worth many times the cost of a disconnect switch. The benefits and limitations of a number of possible methods of reliably monitoring HV disconnect switches are assessed. Several methods of powering active devices at HV are noted. It is concluded that the most reliable way of monitoring switch position at reasonable cost would use a passive hermetically-sealed blade-position sensor located at HV, with a fibre-optic link between HV and ground. Separate sensors would be used for open and closed position indication. For maximum reliability the fibre-optic link would continue into the relay building. A passive magnetically actuated fibre-optic sensor has been built which demonstrates the feasibility of the concept. The sensor monitors blade position relative to the jaws in three dimensions with high resolution. A design for an improved passive magneto-optic sensor has significantly lower optical losses, allowing a single fibre-optic loop and 3 sensors to monitor closure of all phases of a disconnect switch. A similar loop would monitor switch opening. The improved sensor has a solid copper housing to provide greater immunity to fault currents, and to protect it from the environment and from physical damage. Two methods of providing a protected path for fibre-optics passing from HV to ground are proposed, one using a hollow porcelain switch-support insulator and the other using an additional small-diameter polymer insulator with optical fibres imbedded in its fibreglass core. A number of improvements are recommended which can be made to existing switches to increase their reliability. 16 refs., 13 figs., 1 tab.

Validating an infrared thermal switch as a novel access technology

Directory of Open Access Journals (Sweden)

Memarian Negar

2010-08-01

Full Text Available Abstract Background Recently, a novel single-switch access technology based on infrared thermography was proposed. The technology exploits the temperature differences between the inside and surrounding areas of the mouth as a switch trigger, thereby allowing voluntary switch activation upon mouth opening. However, for this technology to be clinically viable, it must be validated against a gold standard switch, such as a chin switch, that taps into the same voluntary motion. Methods In this study, we report an experiment designed to gauge the concurrent validity of the infrared thermal switch. Ten able-bodied adults participated in a series of 3 test sessions where they simultaneously used both an infrared thermal and conventional chin switch to perform multiple trials of a number identification task with visual, auditory and audiovisual stimuli. Participants also provided qualitative feedback about switch use. User performance with the two switches was quantified using an efficiency measure based on mutual information. Results User performance (p = 0.16 and response time (p = 0.25 with the infrared thermal switch were comparable to those of the gold standard. Users reported preference for the infrared thermal switch given its non-contact nature and robustness to changes in user posture. Conclusions Thermal infrared access technology appears to be a valid single switch alternative for individuals with disabilities who retain voluntary mouth opening and closing.

Pacemaker reed switch behavior in 0.5, 1.5, and 3.0 Tesla magnetic resonance imaging units: are reed switches always closed in strong magnetic fields?

Science.gov (United States)

Luechinger, Roger; Duru, Firat; Zeijlemaker, Volkert A; Scheidegger, Markus B; Boesiger, Peter; Candinas, Reto

2002-10-01

MRI is established as an important diagnostic tool in medicine. However, the presence of a cardiac pacemaker is usually regarded as a contraindication for MRI due to safety reasons. The aim of this study was to investigate the state of a pacemaker reed switch in different orientations and positions in the main magnetic field of 0.5-, 1.5-, and 3.0-T MRI scanners. Reed switches used in current pacemakers and ICDs were tested in 0.5-, 1.5-, and 3.0-T MRI scanners. The closure of isolated reed switches was evaluated for different orientations and positions relative to the main magnetic field. The field strengths to close and open the reed switch and the orientation dependency of the closed state inside the main magnetic field were investigated. The measurements were repeated using two intact pacemakers to evaluate the potential influence of the other magnetic components, like the battery. If the reed switches were oriented parallel to the magnetic fields, they closed at 1.0 +/- 0.2 mT and opened at 0.7 +/- 0.2 mT. Two different reed switch behaviors were observed at different magnetic field strengths. In low magnetic fields ( 200 mT), the reed switches opened in 50% of all tested orientations. No difference between the three scanners could be demonstrated. The reed switches showed the same behavior whether they were isolated or an integral part of the pacemakers. The reed switch in a pacemaker or an ICD does not necessarily remain closed in strong magnetic fields at 0.5, 1.5, or 3.0 T and the state of the reed switch may not be predictable with certainty in clinical situations.

Repetitive switching for an electromagnetic rail gun

Science.gov (United States)

Gruden, J. M.

1983-12-01

Previous testing on a repetitive opening switch for inductive energy storage has proved the feasibility of the rotary switch concept. The concept consists of a rotating copper disk (rotor) with a pie-shaped insulator section and brushes which slide along each of the rotor surfaces. While on top of the copper surface, the brushes and rotor conduct current allowing the energy storage inductor to charge. When the brushes slide onto the insulator section, the current cannot pass through the rotor and is diverted into the load. This study investigates two new brush designs and a rotor modification designed to improve the current commutating capabilities of the switch. One brush design (fringe fiber) employs carbon fibers on the leading and trailing edge of the brush to increase the resistive commutating action as the switch opens and closes. The other brush design uses fingers to conduct current to the rotor surface, effectively increasing the number of brush contact points. The rotor modification was the placement of tungsten inserts at the copper-insulator interfaces.

Switched Broadband Services For The Home

Science.gov (United States)

Sawyer, Don M.

1990-01-01

In considering the deployment of fiber optics to the residence, two critical questions arise: what are the leading services that could be offered to justify the required investment; and what is the nature of the business that would offer these services to the consumer ? This talk will address these two questions together with the related issue of how the "financial engine" of today's television distribution infrastructure - TV advertising - would be affected by an open access system based on fiber optics coupled with broadband switching. On the business side, the talk concludes that the potential for open ended capacity expansion, fair competition between service providers, and new interactive services inherent in an open access, switched broadband system are the critical items in differentiating it from existing video and TV distribution systems. On the question of broadband services, the talk will highlight several new opportunities together with some findings from recent market research conducted by BNR. The talk will show that there are variations on existing services plus many new services that could be offered and which have real consumer appeal. The postulated open access system discussed here is visualized as having ultimately 1,000 to 2,000 video channels available to the consumer. Although this may appear to hopelessly fragment the TV audience and destroy the current TV advertising infrastructure, the technology of open access, switched broadband will present many new advertising techniques, which have the potential to be far more effective than those available today. Some of these techniques will be described in this talk.

Dynamics of the Energy Transfer to the Load During the Operation of a Plasma Opening Switch

International Nuclear Information System (INIS)

Dolinsky, Yu.; Krasik, Ya.E.; Felsteiner, J.

1999-01-01

The main efforts of the theoretical and experimental studies related to the Plasma Opening Switch (POS) have been devoted to the understanding of an anomalous fast magnetic field penetration through the plasma. At present this phenomenon can be explained based on the electron magnetohydrodynamic theory.l The second important phenomenon is related with POS opening. Existing models explain POS opening as a result of cut-off of the electron current component in the double layer2 by self-magnetic field of the POS current or by the increase of the Hall potential in the current layer due to ion erosion.3 Nevertheless both models consider POS opening in the region which was preliminary occupied by the plasma. In a recent experiment4 it was shown that the POS opening is related with a fast charged particle flow in the downstream region, namely at the load. In this work we present results of theoretical studies of the phase of the POS operation when the self-magnetic field of the POS current appears at the downstream side of the plasma. Our study has been done within the framework of two-fluid magnetohydrodynamic theory. Taking into account the Hall electric field which is responsible for a strong ion acceleration in the axial direction, we found the velocity of the ions. In addition we show, that due to the inductive electric field caused by the motion of the axial current carrying plasma, the velocity of the magnetic field penetration is equal to the Alfven velocity

Light-Induced Switching of Tunable Single-Molecule Junctions

KAUST Repository

Sendler, Torsten; Luka-Guth, Katharina; Wieser, Matthias; Lokamani; Wolf, Jannic Sebastian; Helm, Manfred; Gemming, Sibylle; Kerbusch, Jochen; Scheer, Elke; Huhn, Thomas; Erbe, Artur

2015-01-01

A major goal of molecular electronics is the development and implementation of devices such as single-molecular switches. Here, measurements are presented that show the controlled in situ switching of diarylethene molecules from their nonconductive to conductive state in contact to gold nanoelectrodes via controlled light irradiation. Both the conductance and the quantum yield for switching of these molecules are within a range making the molecules suitable for actual devices. The conductance of the molecular junctions in the opened and closed states is characterized and the molecular level E 0, which dominates the current transport in the closed state, and its level broadening Γ are identified. The obtained results show a clear light-induced ring forming isomerization of the single-molecule junctions. Electron withdrawing side-groups lead to a reduction of conductance, but do not influence the efficiency of the switching mechanism. Quantum chemical calculations of the light-induced switching processes correlate these observations with the fundamentally different low-lying electronic states of the opened and closed forms and their comparably small modification by electron-withdrawing substituents. This full characterization of a molecular switch operated in a molecular junction is an important step toward the development of real molecular electronics devices.

Light-Induced Switching of Tunable Single-Molecule Junctions

KAUST Repository

Sendler, Torsten

2015-04-16

A major goal of molecular electronics is the development and implementation of devices such as single-molecular switches. Here, measurements are presented that show the controlled in situ switching of diarylethene molecules from their nonconductive to conductive state in contact to gold nanoelectrodes via controlled light irradiation. Both the conductance and the quantum yield for switching of these molecules are within a range making the molecules suitable for actual devices. The conductance of the molecular junctions in the opened and closed states is characterized and the molecular level E 0, which dominates the current transport in the closed state, and its level broadening Γ are identified. The obtained results show a clear light-induced ring forming isomerization of the single-molecule junctions. Electron withdrawing side-groups lead to a reduction of conductance, but do not influence the efficiency of the switching mechanism. Quantum chemical calculations of the light-induced switching processes correlate these observations with the fundamentally different low-lying electronic states of the opened and closed forms and their comparably small modification by electron-withdrawing substituents. This full characterization of a molecular switch operated in a molecular junction is an important step toward the development of real molecular electronics devices.

OpenFlow cookbook

CERN Document Server

Smiler S, Kingston

2015-01-01

This book is intended for network protocol developers, SDN controller application developers, and academics who would like to understand and develop their own OpenFlow switch or OpenFlow controller in any programming language. With basic understanding of OpenFlow and its components, you will be able to follow the recipes in this book.

High-power subnanosecond operation of a bistable optically controlled semiconductor switch (BOSS)

International Nuclear Information System (INIS)

Stoudt, D.C.; Richardson, M.A.; Demske, D.L.; Roush, R.A.; Eure, K.W.

1994-01-01

Recent high-power, subnanosecond-switching results of the Bistable Optically controlled Semiconductor Switch (BOSS) are presented. The process of persistent photoconductivity followed by photo-quenching have been demonstrated at megawatt power levels in copper-compensated, silicon-doped, semi-insulating gallium arsenide. These processes allow a switch to be developed that can be closed by the application of one laser pulse and opened by the application of a second laser pulse with a wavelength equal to twice that of the first laser. Switch closure is primarily achieved by elevating electrons from a deep copper center which has been diffused into the material. The opening phase is a two-step process which relies initially on the absorption of the 2-μm laser causing electrons to be elevated from the valance band back into the copper center, and finally on the recombination of electrons in the conduction band with boles in the valance band. The second step requires a sufficient concentration of recombination centers (RC) in the material for opening to occur in the subnanosecond regime. These RC's are generated in the bulk GaAs material by fast-neutron irradiation (∼ 1 MeV) at a fluence of about 3 x 10 15 cm -2 . High-power switching results which demonstrate that the BOSS switch can be opened in the subnanosecond regime are presented for the first time. Neutron-irradiated BOSS devices have been opened against a rising electric field of about 20 kV/cm (10 kV) in a time less than one nanosecond. Kilovolt electrical pulses have been generated with a FWHM of roughly 250 picoseconds

Microwave pulse generation by photoconductive switching

Energy Technology Data Exchange (ETDEWEB)

Pocha, M.D.; Druce, R.L.

1989-03-14

Laser activated photoconductive semiconductor switching shows significant potential for application in high power microwave generation. Primary advantages of this concept are: small size, light weight, ruggedness, precise timing and phasing by optical control, and the potential for high peak power in short pulses. Several concepts have been suggested for microwave generation using this technology. They generally fall into two categories (1) the frozen wave generator or (2) tuned cavity modulation, both of which require only fast closing switches. We have been exploring a third possibility requiring fast closing and opening switches, that is the direct modulation of the switch at microwave frequencies. Switches have been fabricated at LLNL using neutron irradiated Gallium Arsenide which exhibit response times as short as 50 ps at low voltages. We are in the process of performing high voltage tests. So far, we have been able to generate 2.4 kV pulses with approximately 340 ps response time (FWHM) using approximately a 200..mu..J optical pulse. Experiments are continuing to increase the voltage and improve the switching efficiency. 3 refs., 6 figs.

Microwave pulse generation by photoconductive switching

Science.gov (United States)

Pocha, M. D.; Druce, R. L.

1989-03-01

Laser activated photoconductive semiconductor switching shows significant potential for application in high power microwave generation. Primary advantages of this concept are: small size, light weight, ruggedness, precise timing and phasing by optical control, and the potential for high peak power in short pulses. Several concepts have been suggested for microwave generation using this technology. They generally fall into two categories: (1) the frozen wave generator, or (2) tuned cavity modulation, both of which require only fast closing switches. We have been exploring a third possibility requiring fast closing and opening switches, that is the direct modulation of the switch at microwave frequencies. Switches have been fabricated at LLNL using neutron irradiated Gallium Arsenide which exhibit response times as short as 50 ps at low voltages. We are in the process of performing high voltage tests. So far, we have been able to generate 2.4 kV pulses with approximately 340 ps response time (FWHM) using approximately a 200 microJ optical pulse. Experiments are continuing to increase the voltage and improve the switching efficiency.

The Robustness of Stochastic Switching Networks

OpenAIRE

Loh, Po-Ling; Zhou, Hongchao; Bruck, Jehoshua

2009-01-01

Many natural systems, including chemical and biological systems, can be modeled using stochastic switching circuits. These circuits consist of stochastic switches, called pswitches, which operate with a fixed probability of being open or closed. We study the effect caused by introducing an error of size ∈ to each pswitch in a stochastic circuit. We analyze two constructions – simple series-parallel and general series-parallel circuits – and prove that simple series-parallel circuits are robus...

Fluid simulation of the conduction phase of the plasma erosion opening switch

International Nuclear Information System (INIS)

Grossmann, J.M.; Mosher, D.; Ottinger, P.F.

1987-01-01

The conduction phase of the plasma erosion openings switch (PEOS) is studied using a 1 1/2-D electromagnetic two-fluid code. The focus of this work is on understanding how two effects, a current-limiting model of electron emission, and the magnetic insulation of electrons at the cathode, determine current conduction in the plasma. Simulations are performed in the parameter regimes of the Gamble I, POP, and PBFA II pulsed power generators, and previous low-density, short-rise time simulations of the PEOS. Fluid code results are compared to a 1-D analytic theory and to the Gamble I and POP experiments. Good agreement between theory and simulation, but mixed agreement between simulation and experiment is found. Experimental Β-field measurements on POP show weaker j x Β compression than the simulation. Current penetration and plasma current channels qualitatively similar to experimental observation are found in the Gamble I regime. However, magnetic insulation of electrons emitted from the cathode bunches the electron flow into narrower current channels than observed experimentally. In several cases, the presence of an electron-scattering or energy-loss mechanism near the cathode must be invoked to overcome magnetic insulation and widen the current channels

Subnanosecond, high-voltage photoconductive switching in GaAs

Science.gov (United States)

Druce, Robert L.; Pocha, Michael D.; Griffin, Kenneth L.; O'Bannon, Jim

1991-03-01

We are conducting research on the switching properties of photoconductive materials to explore their potential for generating highpower microwaves (HPM) and for high reprate switching. We have investigated the performance of Gallium Arsenide (GaAs) in linear mode (the conductivity of the device follows the optical pulse) as well as an avalanchelike mode (the optical pulse only controls switch closing) . Operating in the unear mode we have observed switch closing times of less than 200 Ps with a 100 ps duration laser pulse and opening times of less than 400 ps at several kV/cm fields using neutron irradiated GaAs. In avalanche and lockon modes high fields are switched with lower laser pulse energies resulting in higher efficiencies but with measurable switching delay and jitter. We are currently investigating both large area (1 cm2) and small area 1 mm2) switches illuminated by AlGaAs laser diodes at 900 nm and Nd:YAG lasers at 1. 06 tim.

Advances in high voltage power switching with GTOs

International Nuclear Information System (INIS)

Podlesak, T.F.

1990-01-01

The control of high voltage at high power, particularly opening switches, has been difficult in the past. Using gate turnoff thyristors (GTOs) arranged in series enables large currents to be switched at high voltage. The authors report a high voltage opening switch has been successfully demonstrated. This switch uses GTOs in series and successfully operates at voltages higher than the rated voltage of the individual devices. It is believed that this is the first time this has been successfully demonstrated, in that GTOs have been operated in series before, but always in a manner as to not exceed the voltage capability of the individual devices. In short, the devices have not worked together, sharing the voltage, but one device has been operated using several backup devices. Of particular interest is how well the individual devices share the voltage applied to them. Equal voltage sharing between devices is absolutely essential, in order to not exceed the voltage rating of any of the devices in the series chain. This is accomplished at high (microsecond) switching speeds. Thus, the system is useful for high frequency applications as well as high power, making for a flexible circuit system element. This demonstration system is rated at 5 KV and uses 1 KV devices. A larger 24 KV system is under design and will use 4.5 KV devices. In order to design the 24 KV switch, the safe operating area of the large devices must be known thoroughly

Measurement of performance parameters of plasma source for plasma opening switch on Qiangguang-Ⅰ generator

International Nuclear Information System (INIS)

Luo Weixi; Zeng Zhengzhong; Lei Tianshi; Wang Liangping; Hu Yixiang; Sun Tieping; Huang Tao

2012-01-01

The plasma source (cable guns) of the plasma opening switch (POS) on Qiangguang Ⅰ generator was chosen as the study object. The plasma source performance was investigated by using charge collectors. Experimental results show that the plasma ejection density is positively correlated with the structural parameter, the distance between gun core tip and muzzle plane, and the plasma ejection velocity is negatively correlated with the parameter. The increasing rate of plasma ejection density is less than that of drive current. As far as a plasma source with tens of cable plasma guns is concerned, the influence of single cable gun's discharge dispersancy on plasma uniformity is little. Analysis of uncertainty shows that the uncertainty of measurement can be reduced by increasing the number of experiments and averaging the results. The combined standard uncertainty of plasma ejection density is less than 10%. (authors)

Two-dimensional electron flow in pulsed power transmission lines and plasma opening switches

International Nuclear Information System (INIS)

Church, B.W.; Longcope, D.W.; Ng, C.K.; Sudan, R.N.

1991-01-01

The operation of magnetically insulated transmission lines (MITL) and the interruption of current in a plasma opening switch (POS) are determined by the physics of the electrons emitted by the cathode surface. A mathematical model describes the self-consistent two-dimensional flow of an electron fluid. A finite element code, FERUS, has been developed to solve the two equations which describe Poisson's and Ampere's law in two dimensions. The solutions from this code are obtained for parameters where the electron orbits are considerably modified by the self-magnetic field of the current. Next, the self-insulated electron flow in a MITL with a step change in cross-section is studied using a conventional two-dimensional fully electromagnetic particle-in-cell code, MASK. The equations governing two-dimensional quasi-static electron flow are solved numerically by a third technique which is suitable for predicting current interruption in a POS. The object of the study is to determine the critical load impedance, Z CL , required for current interruption for a given applied voltage, cathode voltage and plasma length. (author). 9 refs, 5 figs

State Recognition of High Voltage Isolation Switch Based on Background Difference and Iterative Search

Science.gov (United States)

Xu, Jiayuan; Yu, Chengtao; Bo, Bin; Xue, Yu; Xu, Changfu; Chaminda, P. R. Dushantha; Hu, Chengbo; Peng, Kai

2018-03-01

The automatic recognition of the high voltage isolation switch by remote video monitoring is an effective means to ensure the safety of the personnel and the equipment. The existing methods mainly include two ways: improving monitoring accuracy and adopting target detection technology through equipment transformation. Such a method is often applied to specific scenarios, with limited application scope and high cost. To solve this problem, a high voltage isolation switch state recognition method based on background difference and iterative search is proposed in this paper. The initial position of the switch is detected in real time through the background difference method. When the switch starts to open and close, the target tracking algorithm is used to track the motion trajectory of the switch. The opening and closing state of the switch is determined according to the angle variation of the switch tracking point and the center line. The effectiveness of the method is verified by experiments on different switched video frames of switching states. Compared with the traditional methods, this method is more robust and effective.

49 CFR 236.528 - Restrictive condition resulting from open hand-operated switch; requirement.

Science.gov (United States)

2010-10-01

... SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Rules and...-operated switch three-eighths inch or more, or hand-operated switch is not locked where facing point lock with circuit controller is used, the resultant restrictive condition of an automatic train stop or...

Sequential magnetic switching in Fe/MgO(001) superlattices

Science.gov (United States)

Magnus, F.; Warnatz, T.; Palsson, G. K.; Devishvili, A.; Ukleev, V.; Palisaitis, J.; Persson, P. O. Å.; Hjörvarsson, B.

2018-05-01

Polarized neutron reflectometry is used to determine the sequence of magnetic switching in interlayer exchange coupled Fe/MgO(001) superlattices in an applied magnetic field. For 19.6 Å thick MgO layers we obtain a 90∘ periodic magnetic alignment between adjacent Fe layers at remanence. In an increasing applied field the top layer switches first followed by its second-nearest neighbor. For 16.4 Å MgO layers, a 180∘ periodic alignment is obtained at remanence and with increasing applied field the layer switching starts from the two outermost layers and proceeds inwards. This sequential tuneable switching opens up the possibility of designing three-dimensional magnetic structures with a predefined discrete switching sequence.

Switching robust control synthesis for teleoperation via dwell time conditions

NARCIS (Netherlands)

López Martínez, C.A.; van de Molengraft, M.J.G.; Steinbuch, M.; Auvray, M.; Duriez, C.

2014-01-01

Control design for bilateral teleoperation is still an open problem, given that it is desirable to meet a proper balance in the inherent trade-off between transparency and stability. We propose the use of switching robust control, in which smooth switching among controllers is achieved by the

Effects of switching from olanzapine to aripiprazole on the metabolic profiles of patients with schizophrenia and metabolic syndrome: a double-blind, randomized, open-label study [Corrigendum

Directory of Open Access Journals (Sweden)

Wani RA

2015-03-01

Full Text Available Wani RA, Dar MA, Chandel RK, et al Title of paper should have been “Effects of switching from olanzapine to aripiprazole on the metabolic profiles of patients with schizophrenia and metabolic syndrome: a randomized, open-label study”.  Read the original paper 

Modeling of plasma flow switches at low, intermediate and high energies

International Nuclear Information System (INIS)

Bowers, R.L.; Brownell, J.H.; Greene, A.E.; Peterson, D.L.; Roderick, N.; Turchi, P.

1992-01-01

Inductively stored pulsed power technology has been used over the past thirty years to produce multi-megaamp currents to implode low inductance loads and produce x-radiation. Because of the large difference in timescales for the delivery of magnetic energy to the load and the desire for high power x-radiation output (short timescale for the implosion), most inductively stored systems require at least one opening switch. The design and understanding of fast, efficient opening switches for multi-megaamp systems represents a long standing problem in pulsed power research. The Los Alamos Foil Implosion Project uses inductively stored magnetic energy to implode thin metallic liners. A plasma flow switch (PFS) has been investigated as the final pulse shaping step for this systems. The PFS consists of a wire array and a barrier foil located upstream from the load region. Several stages can be identified in the performance of the plasma flow switch. These are: (1) the vaporization of the wire array; (2) the assembly of the initiated plasma on tie barrier foil to form the switch plasma; (3) the motion of the switch plasma down the coaxial barrel; and (4) current switching to the load (the actual switching stage). The fourth stage affects the switch's efficiency, as well as the quality of the load implosion. Instabilities may develop during any of these four stages, and their presence may seriously degrade the structure of the switch plasma. Two primary criteria may be used to characterize good switching. The first is switching efficiency. A second criterion is transferred to the load during or after switching. This paper summarizes the computational design of the PFS experiments carried out on Pegasus 1. We conclude by considering the implications of these results for the design of a PFS for the higher energy regime (Procyon) regime

The Atlas load protection switch

CERN Document Server

Davis, H A; Dorr, G; Martínez, M; Gribble, R F; Nielsen, K E; Pierce, D; Parsons, W M

1999-01-01

Atlas is a high-energy pulsed-power facility under development to study materials properties and hydrodynamics experiments under extreme conditions. Atlas will implode heavy liner loads (m~45 gm) with a peak current of 27-32 MA delivered in 4 mu s, and is energized by 96, 240 kV Marx generators storing a total of 23 MJ. A key design requirement for Atlas is obtaining useful data for 95601130f all loads installed on the machine. Materials response calculations show current from a prefire can damage the load requiring expensive and time consuming replacement. Therefore, we have incorporated a set of fast-acting mechanical switches in the Atlas design to reduce the probability of a prefire damaging the load. These switches, referred to as the load protection switches, short the load through a very low inductance path during system charge. Once the capacitors have reached full charge, the switches open on a time scale short compared to the bank charge time, allowing current to flow to the load when the trigger pu...

Switching from adalimumab to tofacitinib in the treatment of patients with rheumatoid arthritis.

Science.gov (United States)

Genovese, Mark C; van Vollenhoven, Ronald F; Wilkinson, Bethanie; Wang, Lisy; Zwillich, Samuel H; Gruben, David; Biswas, Pinaki; Riese, Richard; Takiya, Liza; Jones, Thomas V

2016-06-23

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). The aim of this study was to explore the safety and efficacy of open-label tofacitinib following blinded treatment with adalimumab or tofacitinib for moderate to severe RA. Analyses included patients treated with adalimumab 40 mg once every 2 weeks or tofacitinib 10 mg twice daily (BID) with background methotrexate (MTX) in a 12-month randomized study (NCT00853385), who subsequently received tofacitinib 10 mg BID (with/without background MTX) in an open-label extension (NCT00413699). Patients with treatment-related serious adverse events (AEs) and serious or recurrent infections in the index study were excluded from the extension study. Exposure-adjusted incidence rates of safety-related events were assessed in 3-month and 12-month periods in the year before and in the year after switching. Efficacy was assessed 3 months before, at the time of, and 3 months after switching. There were 233 (107 adalimumab to tofacitinib 10 mg BID, 126 blinded to open-label tofacitinib 10 mg BID) patients included in these analyses. Patients in both treatment sequences had similar incidence rates (per 100 patient-years) of discontinuation due to AEs, serious AEs, and serious infections in the year before and in the year after switching. Incidence rates of AEs were increased in the first 3 months after switching compared with the last 3 months before switching in both treatment groups. Switching from either blinded adalimumab or tofacitinib to open-label tofacitinib resulted in numerically higher incidence of responders for signs and symptoms of disease and improved physical function. Treatment can be directly switched from adalimumab to tofacitinib. A similar safety and efficacy profile was seen when patients received open-label tofacitinib after receiving either blinded adalimumab or tofacitinib. ClinicalTrials.gov Identifiers: NCT00853385 , registered 27 February 2009; NCT

Subnanosecond, high voltage photoconductive switching in GaAs

Energy Technology Data Exchange (ETDEWEB)

Druce, R.L.; Pocha, M.D.; Griffin, K.L. (Lawrence Livermore National Lab., CA (USA)); O' Bannon, B.J. (Rockwell International Corp., Anaheim, CA (USA))

1990-01-01

We are conducting research on the switching properties of photoconductive materials to explore their potential for generating high-power microwaves (HPM) and for high rep-rate switching. We have investigated the performance of Gallium Arsenide (GaAs) in linear mode (the conductivity of the device follows the optical pulse) as well as an avalanche-like mode (the optical pulse only controls switch closing). Operating in the linear mode, we have observed switch closing times of less than 200 ps with a 100 ps duration laser pulse and opening times of less than 400 ps at several kV/cm fields using neutron irradiated GaAs. In avalanche and lock-on modes, high fields are switched with lower laser pulse energies, resulting in higher efficiencies; but with measurable switching delay and jitter. We are currently investigating both large area (1 cm{sup 2}) and small area (<1 mm{sup 2}) switches illuminated by AlGaAs laser diodes at 900 nm and Nd:YAG lasers at 1.06 {mu}m.

IGBT: a solid state switch

International Nuclear Information System (INIS)

Chatroux, D.; Maury, J.; Hennevin, B.

1993-01-01

A Copper Vapour Laser Power Supply has been designed using a solid state switch consisting in eighteen Isolated Gate Bipolar Transistors (IGBT), -1200 volts, 400 Amps, each-in parallel. This paper presents the Isolated Gate Bipolar Transistor (IGBTs) replaced in the Power Electronic components evolution, and describes the IGBT conduction mechanism, presents the parallel association of IGBTs, and studies the application of these components to a Copper Vapour Laser Power Supply. The storage capacitor voltage is 820 volts, the peak current of the solid state switch is 17.000 Amps. The switch is connected on the primary of a step-up transformer, followed by a magnetic modulator. The reset of the magnetic modulator is provided by part of the laser reflected energy with a patented circuit. The charging circuit is a resonant circuit with a charge controlled by an IGBT switch. When the switch is open, the inductance energy is free-wheeled by an additional winding and does not extend the charging phase of the storage capacitor. The design allows the storage capacitor voltage to be very well regulated. This circuit is also patented. The electric pulse in the laser has 30.000 Volt peak voltage, 2000 Amp peak current, and is 200 nanoseconds long, for a 200 Watt optical power Copper Vapour Laser

Improvement of Matrix Converter Drive Reliability by Online Fault Detection and a Fault-Tolerant Switching Strategy

DEFF Research Database (Denmark)

Nguyen-Duy, Khiem; Liu, Tian-Hua; Chen, Der-Fa

2011-01-01

The matrix converter system is becoming a very promising candidate to replace the conventional two-stage ac/dc/ac converter, but system reliability remains an open issue. The most common reliability problem is that a bidirectional switch has an open-switch fault during operation. In this paper, a...

Optical processes in the performance and recovery of gas-phase switches

International Nuclear Information System (INIS)

Gundersen, M.

1982-01-01

In this paper several optical processes that may be used to affect gas-phase switch performance and operation are discussed, and approaches using a laser to increase recovery rates of switches are presented. In the latter the laser is used during the recovery phase rather than the conductive or closure phase. This papper suggests that it should be possible to use a low-power laser (e.g., one that is technologically feasible to use as part of a switch) to assist in opening the switch by quenching excited atomic and/or molecular species. The application of laser-induced energy extraction to gas-phase switches is also discussed

Progress in switching technology for METS systems

International Nuclear Information System (INIS)

Honig, E.M.; Swannack, C.E.; Warren, R.W.; Whitaker, D.H.

1977-01-01

Three distinct sets of switching requirements have emerged from design optimization studies of large superconducting magnetic energy storage systems, such as the METS system to power the adiabatic plasma compression field in the proposed theta-pinch SFTR. Extremely low joule loss cryogenic disconnects are required between storage coils in the liquid helium environment to allow charging the coils in series over a prolonged time, then to isolate the coils for parallel fast discharging into the load. Another switch must break the current in the series charging loop and absorb the energy from the stray inductance. This action will allow the subsequent opening of the cryogenic disconnects under near zero current condition. The current now has been transferred to the many paralleled circuits, each containing a high current, high voltage interrupter. The opening and arc commutation of the interrupter starts the energy transfer into the load. The primary activities associated with cryogenic disconnect have been testing and development of contact materials, configurations, and closing forces for carrying 26 kA with a resistance less than 40 nΩ, and development of an actuating system that is both reliable and fast acting in a liquid helium environment. The charging loop switch will include a continuous duty switch and a vacuum interrupter. The continuous duty switch resistance can be an order of magnitude larger than that of the cryogenic disconnect because it does not present a refrigeration load. The HVDC interrupter must break 26 kA and withstand 60 kV during the energy transfer time of 700 μs. Testing in progress already has shown successful interruption using single vacuum interrupters up to 31 kA and 66 kV

The Transistor as Low Level Switch

Energy Technology Data Exchange (ETDEWEB)

Lyden, Anders

1963-10-15

The common collector transistor switch has in the on state with open emitter a certain offset voltage U{sub EK} {approx_equal} -kT/qB{sub N}. This expression is derived in a new, more physical way. It is further shown at which emitter current the current amplification factor B{sub N} should be measured to get a correct value for the above expression. The collector current I at zero collector voltage I{sub K} = I{sub 0}(exp(qU{sub E}/kT) - 1) extremely well. Substitution of I{sub EBO} and I{sub KBO} by I{sub 0} in Eber's and Moll's relations consequently improves these equations and the characteristics of the transistor switch can be better determined. At switching on and off transients appear across the switch. The influence of the 'spike' at switching off can be described by an current I{sub SPIKE} which is easy to calculate. I{sub SPIKE} is approximately dependent only on the base - emitter depletion layer capacitance and the chopper frequency f{sub 0}. Some compensated switches have lower drift than the drift in U{sub EK}. They may, for example, have a temperature drift < 0.2 {mu}V/deg C and a long time drift < 2 {mu}V/week. Some compensated switches also have I{sub SPIKE} < 10{sup -12} f{sub 0}A. The static offset current in the off state can easily be made < 10{sup -12} A.

Chemical switches and logic gates based on surface modified semiconductors

Energy Technology Data Exchange (ETDEWEB)

Konrad, Szacilowski; Wojciech, Macyk [Jagiellonian Univ., Dept. of Chemistry, Krakow (Poland)

2006-02-15

Photoelectrochemical properties of multicomponent photo-electrodes based on titanium dioxide and cadmium sulfide powders modified with hexacyanoferrate complexes have been examined. Photocurrent responses were recorded as functions of applied potential and photon energy. Surprisingly, the photocurrent can be switched between positive and negative values as a result of potential or photon energy changes. This new effect called Photo Electrochemical Photocurrent Switching (PEPS) opens a possibility of new chemical switches and logic gates construction. Boolean logic analysis and a tentative mechanism of the device are discussed. (authors)

Subnanosecond photoconductive switching in GaAs

Energy Technology Data Exchange (ETDEWEB)

Druce, R.L.; Pocha, M.D.; Griffin, K.L.

1991-04-01

We are conducting research in photoconductive switching for the purpose of generating microwave pulses with amplitudes up to 50 kV. This technology has direct application to impulse radar and HPM sources. We are exploiting the very fast recombination rates of Gallium Arsenide (GaAs) to explore the potential of GaAs as an on-off switch when operating in the linear mode (the linear mode is defined such that one carrier pair is generated for each photon absorbed). In addition, we are exploring the potential GaAs to act as a closing switch in ``avalanche`` mode at high fields. We have observed switch closing times of less than 200 psec with a 100 psec duration laser pulse and opening times of less than 400 psec with neutron irradiated GaAs at fields of tens of kV/cm. If the field is increased and the laser energy decreased, the laser can be used to trigger photoconductive switches into ``avalanche`` mode of operation in which carrier multiplication occurs. This mode of operation is quite promising since the switches close in less than 1 nsec while realizing significant energy gain (ratio of electrical energy in the pulse to optical trigger energy). We are currently investigating both large area (1 sq cm) and small area (< 1 sq mm) switches illuminated by GaAlAs laser diodes at 900 nm and Nd:YAG lasers at 1.06 micrometers. Preliminary results indicate that the closing time of the avalanche switches depends primarily on the material properties of the devices with closing times of 300--1300 psec at voltages of 6--35 kV. We will present experimental results for linear, lock on and avalanche mode operation of GaAs photoconductive switches and how these pulses may be applied to microwave generation. 3 refs.

Subnanosecond photoconductive switching in GaAs

Energy Technology Data Exchange (ETDEWEB)

Druce, R.L.; Pocha, M.D.; Griffin, K.L.

1991-04-01

We are conducting research in photoconductive switching for the purpose of generating microwave pulses with amplitudes up to 50 kV. This technology has direct application to impulse radar and HPM sources. We are exploiting the very fast recombination rates of Gallium Arsenide (GaAs) to explore the potential of GaAs as an on-off switch when operating in the linear mode (the linear mode is defined such that one carrier pair is generated for each photon absorbed). In addition, we are exploring the potential GaAs to act as a closing switch in avalanche'' mode at high fields. We have observed switch closing times of less than 200 psec with a 100 psec duration laser pulse and opening times of less than 400 psec with neutron irradiated GaAs at fields of tens of kV/cm. If the field is increased and the laser energy decreased, the laser can be used to trigger photoconductive switches into avalanche'' mode of operation in which carrier multiplication occurs. This mode of operation is quite promising since the switches close in less than 1 nsec while realizing significant energy gain (ratio of electrical energy in the pulse to optical trigger energy). We are currently investigating both large area (1 sq cm) and small area (< 1 sq mm) switches illuminated by GaAlAs laser diodes at 900 nm and Nd:YAG lasers at 1.06 micrometers. Preliminary results indicate that the closing time of the avalanche switches depends primarily on the material properties of the devices with closing times of 300--1300 psec at voltages of 6--35 kV. We will present experimental results for linear, lock on and avalanche mode operation of GaAs photoconductive switches and how these pulses may be applied to microwave generation. 3 refs.

Subnanosecond photoconductive switching in GaAs

Energy Technology Data Exchange (ETDEWEB)

Druce, R.L.; Pocha, M.D.; Griffin, K.L.

1990-01-01

We are conducting research in photoconductive switching for the purpose of generating microwave pulses with amplitudes up to 50 kV. This technology has direct application to impulse radar and HPM sources. We are exploiting the very fast recombination rates of Gallium Arsenide (GaAs) to explore the potential of GaAs as an on-off switch when operating in the linear mode (the linear mode is defined such that one carrier pair is generated for each photon absorbed). In addition, we are exploring the potential of GaAs to act as a closing switch in avalanche'' mode at high fields. We have observed switch closing times of less than 200 psec with 100 psec duration laser pulse and opening times of less than 400 psec with neutron irradiated GaAs at fields of tens of kV/cm. If the field is increased and the laser energy decreased, the laser can be used to trigger photoconductive switches into an avalanche'' mode of operation in which carrier multiplication occurs. This mode of operation is quite promising since the switches close in less than 1 nsec while realizing significant energy gain (ratio of electrical energy in the pulse to optical trigger energy). We are currently investigating both large are (1 sq cm) and small area (<1 sq mm) switches illuminated by GaAlAs laser diodes at 900 nm and Nd:YAG lasers at 1.06 micrometers. Preliminary results indicate that the closing time of the avalanche switches depends primarily on the material properties of the devices with closing times of 300--1300 psec at voltages of 6-35 kV. We will present experimental results for linear, lock on and avalanche mode operation of GaAs photoconductive switches and how these pulses may be applied to microwave generation. 3 refs., 11 figs.

Subnanosecond photoconductive switching in GaAs

Science.gov (United States)

Druce, R. L.; Pocha, M. D.; Griffin, K. L.

1991-04-01

We are conducting research in photoconductive switching for the purpose of generating microwave pulses with amplitudes up to 50 kV. This technology has direct application to impulse radar and HPM sources. We are exploiting the very fast recombination rates of Gallium Arsenide (GaAs) to explore the potential of GaAs as an on-off switch when operating in the linear mode (the linear mode is defined such that one carrier pair is generated for each photon absorbed). In addition, we are exploring the potential GaAs to act as a closing switch in 'avalanche' mode at high fields. We have observed switch closing times of less than 200 psec with a 100 psec duration laser pulse and opening times of less than 400 psec with neutron irradiated GaAs at fields of tens of kV/cm. If the field is increased and the laser energy decreased, the laser can be used to trigger photoconductive switches into 'avalanche' mode of operation in which carrier multiplication occurs. This mode of operation is quite promising since the switches close in less than 1 nsec while realizing significant energy gain (ratio of electrical energy in the pulse to optical trigger energy). We are currently investigating both large area (1 sq cm) and small area (less than 1 sq mm) switches illuminated by GaAlAs laser diodes at 900 nm and Nd:YAG lasers at 1.06 micrometers. Preliminary results indicate that the closing time of the avalanche switches depends primarily on the material properties of the devices with closing times of 300-1300 psec at voltages of 6-35 kV. We will present experimental results for linear, lock on, and avalanche mode operation of GaAs photoconductive switches and how these pulses may be applied to microwave generation.

Magnetic particle separation using controllable magnetic force switches

International Nuclear Information System (INIS)

Wei Zunghang; Lee, C.-P.; Lai, M.-F.

2010-01-01

Magnetic particle separation is very important in biomedical applications. In this study, a magnetic particle microseparator is proposed that uses micro magnets to produce open/closed magnetic flux for switching on/off the separation. When all magnets are magnetized in the same direction, the magnetic force switch for separation is on; almost all magnetic particles are trapped in the channel side walls and the separation rate can reach 95%. When the magnetization directions of adjacent magnets are opposite, the magnetic force switch for separation is off, and most magnetic particles pass through the microchannel without being trapped. For the separation of multi-sized magnetic particles, the proposed microseparator is numerically demonstrated to have high separation rate.

Simulation of the Plasma Afterglow in the Discharge Gap of a Subnanosecond Switch Based on an Open Discharge in Helium

Science.gov (United States)

Alexandrov, A. L.; Schweigert, I. V.

2018-05-01

The phenomenon of subnanosecond electrical breakdown in a strong electric field observed in an open discharge in helium at pressures of 6-20 Torr can be used to create ultrafast plasma switches triggering into a conducting state for a time shorter than 1 ns. To evaluate the possible repetition rate of such a subnanosecond switch, it is interesting to study the decay dynamics of the plasma remaining in the discharge gap after ultrafast breakdown. In this paper, a kinetic model based on the particle-in-cell Monte Carlo collision method is used to study the dynamics of the plasma afterglow in the discharge gap of a subnanosecond switch operating with helium at a pressure of 6 Torr. The simulation results show that the radiative, collisional-radiative, and three-body collision recombination mechanisms significantly contribute to the afterglow decay only while the plasma density remains higher than 1012 cm-3; the main mechanism of the further plasma decay is diffusion of plasma particles onto the wall. Therefore, the effect of recombination in the plasma bulk is observed only during the first 10-20 μs of the afterglow. Over nearly the same time, plasma electrons become thermalized. The afterglow time can be substantially reduced by applying a positive voltage U c to the cathode. Since diffusive losses are limited by the ion mobility, the additional ion drift toward the wall significantly accelerates plasma decay. As U c increases from 0 to +500 V, the characteristic time of plasma decay is reduced from 35 to 10 μs.

Electro- and photochemical switching of dithienylethene self-assembled monolayers on gold electrodes

DEFF Research Database (Denmark)

Browne, W.R.; Kudernac, T.; Katsonis, N.

2008-01-01

forms of the dithienylethene SAMs is examined and found to be sensitive to the molecular structure of the switch. For the three dithienylethenes, the electrochemical behavior with respect to electrochemical ring opening/closing is retained in the SAMs. In contrast, a marked dependence on the nature...... of the anchoring group is observed upon immobilization in terms of the retention of the photochemical properties observed in solution. For the meta-thiophenol anchor both photochemical ring opening and closing are observed in the SAM, while for the thienyl-thiol-anchored switches the photochemically properties...

Tyr66 acts as a conformational switch in the closed-to-open transition of the SHP-2 N-SH2-domain phosphotyrosine-peptide binding cleft

Directory of Open Access Journals (Sweden)

MacKerell Alexander D

2007-03-01

Full Text Available Abstract Background The N-terminal SH2 domain (N-SH2 of the non-receptor tyrosine phosphatase SHP-2 is involved both in localization of SHP-2 by recognition of phosphotyrosine (pY peptides and self-inhibition of SHP-2 phosphatase activity through the formation of a protein – protein interface with the phosphatase domain. Mutations that disrupt this interface break the coupling between pY-peptide binding cleft conformation and self-inhibition, thereby increasing both SHP-2 phosphatase activity and pY-peptide binding affinity, and are associated with the congenital condition Noonan syndrome and various pediatric leukemias. To better characterize the molecular process involved in N-SH2 pY-dependent binding, we have applied explicit-solvent molecular dynamics simulations to study the closed-to-open transition of the N-SH2 pY-peptide binding cleft. Results The existence of stable conformations in the left-handed helical and the extended regions of Tyr66 φ/ψ space prevent rapid interconversion of the backbone and create a conformational switch such that Tyr66 in a left-handed helical backbone conformation results in an open cleft and in an extended backbone conformation results in a closed cleft. The stable conformations arise from deep, well-localized free-energy minima in the left-handed helical and extended regions of the Tyr66 φ/ψ map. Changing the Tyr66 backbone conformation from extended to left-handed helical induces a closed-to-open transition in the cleft, and the reverse change in backbone conformation induces the reverse, open-to-closed transition. In the open-cleft state, weak solvent-exposed interactions involving the sidechains of Tyr66, Asp40, Lys55, and Gln57 serve to anchor the Tyr66 sidechain to the surface of the protein and away from the binding cleft entrance, thereby facilitating pY-peptide access to the binding cleft. Conclusion The simulations point to a regulatory role for Tyr66 and surrounding residues in SHP-2 function

New fast switches for the Tore Supra ohmic heating circuit

International Nuclear Information System (INIS)

Zunino, K.; Bruneth, J.; Cara, P.; Louart, A.; Santagiustina, A.; Emelyanova, I.; Filippov, F.; Mikailov, N.

2003-01-01

The Tore-Supra ohmic heating circuit is equipped with four fast make switches and one fast opening switch. After many years of operation, it became necessary to substitute this equipment by modern components with similar ratings. An extensive research has been undertaken to find fast switches able to withstand more than 2500 operations per year without maintenance, at a make current of 54 kA, a voltage of 12 kV and with a closing time of less than 15 ms. At the end of the investigation, it was decided to replace the old components by fast mechanical switches proposed by the Efremov Institute and based on a prototype developed for ITER. This paper presents the technical requirements and the characteristics of the switches and describes the operational experience gained with these components during operating campaigns of 2002 and 2003. (authors)

Protection and switching system for the RFX power supply

International Nuclear Information System (INIS)

Browning, J.L.; Gray, J.W.; Mace, T.A.; Varley, G.L.

1986-01-01

The RFX toroidal field power supply comprises a large 4.8MJ (max) modular capacitor bank and four 14MW AC/DC converter flat-top power supply modules. The high fault level associated with the capacitor banks presents a problem in the design of the switching system, since mistiming could produce large currents in the flat-top supplies. The poloidal circuit consists of four groups of magnetising windings connected in series, each with its own flat-top convertor supply and opening switch transfer system. The flat-top converter supplies are needed when the transfer voltage has fallen from approximately 40kV to 1kV. Solutions to the problem of designing a fault-tolerant system which presents no danger to the flat-top converters are described in the paper. The adopted methods make use of hybrid ignitron/mechanical switches to give the required combination of switching speed and current carrying capacity, together with careful attention to the circuit layout of different switching elements. (author)

Sharing Water-related Information to Tackle Changes in the Hydrosphere - for Operational Needs (SWITCH-ON)

Science.gov (United States)

Arheimer, Berit

2015-04-01

Recently, a collaborative EU project started called SWITCH-ON (EU FP7 project No 603587) coordinated by SMHI to support the INSPIRE directive and the Open Data Strategy. The overall goal of the project is to establish a "one-stop-shop" web portal for easy access to European water information. The project will use open data, provide infrastructure for sharing and collaboration, and add value to society and research by repurposing and refining data from various sources. The SWITCH-ON project http://www.water-switch-on.eu/ will establish new forms of water research and facilitate the development of new products and services based on principles of sharing and community building in the water society. The SWITCH-ON objectives are to use open data for implementing: 1) an innovative spatial information platform (SIP) to find, bind, transform and publish data, 2) entirely new forms of collaborative research organised in a Virtual Water-Science Laboratory, open for any research group, 3) fourteen new operational products for water management and awareness, 4) outreach facilities for new water business and knowledge in line with the Europe's smart growth and environmental objectives. This poster will describe the overall project goals and especially the recent progress on developing a Virtual Water-Science Laboratory. Contact: waterswitchon@gmail.com

Q-Switching in a Neodymium Laser

Science.gov (United States)

Holgado, Warein; Sola, Inigo J.; Jarque, Enrique Conejero; Jarabo, Sebastian; Roso, Luis

2012-01-01

We present a laboratory experiment for advanced undergraduate or graduate laser-related classes to study the performance of a neodymium laser. In the experiment, the student has to build the neodymium laser using an open cavity. After that, the cavity losses are modulated with an optical chopper located inside, so the Q-switching regime is…

Assessment of strategies for switching patients from olanzapine to risperidone: A randomized, open-label, rater-blinded study

Directory of Open Access Journals (Sweden)

Berry Sally A

2008-06-01

Full Text Available Abstract Background In clinical practice, physicians often need to change the antipsychotic medications they give to patients because of an inadequate response or the presence of unacceptable or unsafe side effects. However, there is a lack of consensus in the field as to the optimal switching strategy for antipsychotics, especially with regards to the speed at which the dose of the previous antipsychotic should be reduced. This paper assesses the short-term results of strategies for the discontinuation of olanzapine when initiating risperidone. Methods In a 6-week, randomized, open-label, rater-blinded study, patients with schizophrenia or schizoaffective disorder, on a stable drug dose for more than 30 days at entry, who were intolerant of or exhibiting a suboptimal symptom response to more than 30 days of olanzapine treatment, were randomly assigned to the following switch strategies (common risperidone initiation scheme; varying olanzapine discontinuation: (i abrupt strategy, where olanzapine was discontinued at risperidone initiation; (ii gradual 1 strategy, where olanzapine was given at 50% entry dose for 1 week after risperidone initiation and then discontinued; or (iii gradual 2 strategy, where olanzapine was given at 100% entry dose for 1 week, then at 50% in the second week, and then discontinued. Results The study enrolled 123 patients on stable doses of olanzapine. Their mean age was 40.3 years and mean (± standard deviation (SD baseline Positive and Negative Syndrome Scale (PANSS total score of 75.6 ± 11.5. All-cause treatment discontinuation was lowest (12% in the group with the slowest olanzapine dose reduction (gradual 2 and occurred at half the discontinuation rate in the other two groups (25% in abrupt and 28% in gradual 1. The relative risk of early discontinuation was 0.77 (confidence interval 0.61–0.99 for the slowest dose reduction compared with the other two strategies. After the medication was changed, improvements at

Access control mechanism of wireless gateway based on open flow

Science.gov (United States)

Peng, Rong; Ding, Lei

2017-08-01

In order to realize the access control of wireless gateway and improve the access control of wireless gateway devices, an access control mechanism of SDN architecture which is based on Open vSwitch is proposed. The mechanism utilizes the features of the controller--centralized control and programmable. Controller send access control flow table based on the business logic. Open vSwitch helps achieve a specific access control strategy based on the flow table.

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.

Modeling and Analysis of Modal Switching in Networked Transport Systems

International Nuclear Information System (INIS)

Hante, Falk M.; Leugering, Guenter; Seidman, Thomas I.

2009-01-01

We consider networked transport systems defined on directed graphs: the dynamics on the edges correspond to solutions of transport equations with space dimension one. In addition to the graph setting, a major consideration is the introduction and propagation of discontinuities in the solutions when the system may discontinuously switch modes, naturally or as a hybrid control. This kind of switching has been extensively studied for ordinary differential equations, but not much so far for systems governed by partial differential equations. In particular, we give well-posedness results for switching as a control, both in finite horizon open loop operation and as feedback based on sensor measurements in the system

A Two-Level Task Scheduler on Multiple DSP System for OpenCL

Directory of Open Access Journals (Sweden)

Li Tian

2014-04-01

Full Text Available This paper addresses the problem that multiple DSP system does not support OpenCL programming. With the compiler, runtime, and the kernel scheduler proposed, an OpenCL application becomes portable not only between multiple CPU and GPU, but also between embedded multiple DSP systems. Firstly, the LLVM compiler was imported for source-to-source translation in which the translated source was supported by CCS. Secondly, two-level schedulers were proposed to support efficient OpenCL kernel execution. The DSP/BIOS is used to schedule system level tasks such as interrupts and drivers; however, the synchronization mechanism resulted in heavy overhead during task switching. So we designed an efficient second level scheduler especially for OpenCL kernel work-item scheduling. The context switch process utilizes the 8 functional units and cross path links which was superior to DSP/BIOS in the aspect of task switching. Finally, dynamic loading and software managed CACHE were redesigned for OpenCL running on multiple DSP system. We evaluated the performance using some common OpenCL kernels from NVIDIA, AMD, NAS, and Parboil benchmarks. Experimental results show that the DSP OpenCL can efficiently exploit the computing resource of multiple cores.

Arc detector system for extraction switches in LHC CERN

CERN Document Server

Dahlerup-Petersen, K; Kuper, E; Ovchar, V; Zverev, S

2006-01-01

The opening switches, which will be used in case of quenches or other failures in CERN’s future LHC collider to extract the large amounts of energy stored in the magnetic field of the superconducting chains of main dipoles (8 chains with 1350 MJ each) and main quadrupoles (16 chains with about 24 MJ each) consist of an array of series/parallel connected, electro-mechanical D.C. breakers, specifically designed for this particular application. During the opening process the magnet excitation current is transferred from the cluster of breakers to extraction resistors for rapid de-excitation of the magnet chain. An arc detector has been developed in order to facilitate the determination of the need for maintenance interventions on the switches. The paper describes the arc detector and highlight results from operation of the detector with a LHC pilot extraction...

Multi-Valued Spin Switch in a Semiconductor Microcavity

Science.gov (United States)

Paraïso, T. K.; Wouters, M.; Léger, Y.; Morier-Genoud, F.; Deveaudhyphen; Plédran, B.

2011-12-01

In this work, we report on the first realization of multi-valued spin switching in the solid-state. We investigate the physics of spinor bistability with microcavity polaritons in a trap. Spinor interactions lead to special bistability regimes with decoupled thresholds for spin-up and spin-down polaritons. This allows us to establish state-of-the-art spin switching operations. We evidence polarization hysteresis and determine appropriate conditions to achieve spin multistability. For a given excitation condition, three stable spin states coexist for the system. These results open new pathways for the development of innovative spin-based logic gates and memory devices.

Space-charge-mediated anomalous ferroelectric switching in P(VDF-TrEE) polymer films

KAUST Repository

Hu, Weijin

2014-11-12

We report on the switching dynamics of P(VDF-TrEE) copolymer devices and the realization of additional substable ferroelectric states via modulation of the coupling between polarizations and space charges. The space-charge-limited current is revealed to be the dominant leakage mechanism in such organic ferroelectric devices, and electrostatic interactions due to space charges lead to the emergence of anomalous ferroelectric loops. The reliable control of ferroelectric switching in P(VDF-TrEE) copolymers opens doors toward engineering advanced organic memories with tailored switching characteristics.

Widening consumer access to medicines: a comparison of prescription to non-prescription medicine switch in Australia and New Zealand.

Directory of Open Access Journals (Sweden)

Natalie J Gauld

Full Text Available Despite similarities in health systems and Trans-Tasman Harmonization of medicines scheduling, New Zealand is more active than Australia in 'switching' (reclassifying medicines from prescription to non-prescription.To identify and compare enablers and barriers to switch in New Zealand and Australia.We conducted and analyzed 27 in-depth personal interviews with key participants in NZ and Australia and international participants previously located in Australia, and analyzed records of meetings considering switches (2000-2013. Analysis of both sets of data entailed a heuristic qualitative approach that embraced the lead researcher's knowledge and experience.The key themes identified were conservatism and political influences in Australia, and an open attitude, proactivity and flexibility in NZ. Pharmacist-only medicine schedules and individuals holding a progressive attitude were proposed to facilitate switch in both countries. A pharmacy retail group drove many switches in NZ ('third-party switch', unlike Australia. Barriers to switch in both countries included small market sizes, funding of prescription medicines and cost of doctor visits, and lack of market exclusivity. In Australia, advertising limitations for pharmacist-only medicines reportedly discouraged industry from submitting switch applications. Perceptions of pharmacy performance could help or hinder switches.Committee and regulator openness to switch, and confidence in pharmacy appear to influence consumer access to medicines. The pharmacist-only medicine schedule in Australasia and the rise of third-party switch and flexibility in switch in NZ could be considered elsewhere to enable switch.

Widening consumer access to medicines: a comparison of prescription to non-prescription medicine switch in Australia and New Zealand.

Science.gov (United States)

Gauld, Natalie J; Kelly, Fiona S; Emmerton, Lynne M; Buetow, Stephen A

2015-01-01

Despite similarities in health systems and Trans-Tasman Harmonization of medicines scheduling, New Zealand is more active than Australia in 'switching' (reclassifying) medicines from prescription to non-prescription. To identify and compare enablers and barriers to switch in New Zealand and Australia. We conducted and analyzed 27 in-depth personal interviews with key participants in NZ and Australia and international participants previously located in Australia, and analyzed records of meetings considering switches (2000-2013). Analysis of both sets of data entailed a heuristic qualitative approach that embraced the lead researcher's knowledge and experience. The key themes identified were conservatism and political influences in Australia, and an open attitude, proactivity and flexibility in NZ. Pharmacist-only medicine schedules and individuals holding a progressive attitude were proposed to facilitate switch in both countries. A pharmacy retail group drove many switches in NZ ('third-party switch'), unlike Australia. Barriers to switch in both countries included small market sizes, funding of prescription medicines and cost of doctor visits, and lack of market exclusivity. In Australia, advertising limitations for pharmacist-only medicines reportedly discouraged industry from submitting switch applications. Perceptions of pharmacy performance could help or hinder switches. Committee and regulator openness to switch, and confidence in pharmacy appear to influence consumer access to medicines. The pharmacist-only medicine schedule in Australasia and the rise of third-party switch and flexibility in switch in NZ could be considered elsewhere to enable switch.

Electrochemical structure-switching sensing using nanoplasmonic devices

Energy Technology Data Exchange (ETDEWEB)

Patskovsky, Sergiy; Dallaire, Anne-Marie; Blanchard-Dionne, Andre-Pierre; Meunier, Michel [Department of Engineering Physics, Laser Processing and Plasmonics Laboratory, Polytechnique, Montreal, Station Centre-ville, QC (Canada); Vallee-Belisle, Alexis [Laboratory of Biosensors and Nanomachines, Departement de Chimie, Universite de Montreal, QC (Canada)

2015-12-15

In this article, the implementation of electrochemical plasmonic nanostructures functionalized with DNA-based structure-switching sensors is presented. eNanoSPR devices with open and microfluidic measurement cells are developed on the base of nanohole arrays in 100 nm gold film and applied for combined microscopic and electrochemical surface plasmon (eSPR) visualization. eSPR voltammograms and spectroscopy are performed using planar three electrode schematic with plasmonic nanostructure operated as working electrode. Limit of detection of eNanoSPR devices for oligonucleotide hybridization is estimated in the low nanomolar and applications for structure-switching electro-plasmonic sensing in complex liquids are discussed. (copyright 2015 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Supplementary insurance as a switching cost for basic health insurance: Empirical results from the Netherlands.

Science.gov (United States)

Willemse-Duijmelinck, Daniëlle M I D; van de Ven, Wynand P M M; Mosca, Ilaria

2017-10-01

Nearly everyone with a supplementary insurance (SI) in the Netherlands takes out the voluntary SI and the mandatory basic insurance (BI) from the same health insurer. Previous studies show that many high-risks perceive SI as a switching cost for BI. Because consumers' current insurer provides them with a guaranteed renewability, SI is a switching cost if insurers apply selective underwriting to new applicants. Several changes in the Dutch health insurance market increased insurers' incentives to counteract adverse selection for SI. Tools to do so are not only selective underwriting, but also risk rating and product differentiation. If all insurers use the latter tools without selective underwriting, SI is not a switching cost for BI. We investigated to what extent insurers used these tools in the periods 2006-2009 and 2014-2015. Only a few insurers applied selective underwriting: in 2015, 86% of insurers used open enrolment for all their SI products, and the other 14% did use open enrolment for their most common SI products. As measured by our indicators, the proportion of insurers applying risk rating or product differentiation did not increase in the periods considered. Due to the fear of reputation loss insurers may have used 'less visible' tools to counteract adverse selection that are indirect forms of risk rating and product differentiation and do not result in switching costs. So, although many high-risks perceive SI as a switching cost, most insurers apply open enrolment for SI. By providing information to high-risks about their switching opportunities, the government could increase consumer choice and thereby insurers' incentives to invest in high-quality care for high-risks. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of Cisco Open Network Environment (ONE) OpenFlow Controller Implementation

Science.gov (United States)

2014-08-01

Software - Defined Networking ( SDN ), when fully realized, offer many improvements over the current rigid and...functionalities like handshake, connection setup, switch management, and security. 15. SUBJECT TERMS OpenFlow, software - defined networking , Cisco ONE, SDN ...innovating packet-forwarding technologies. Network device roles are strictly defined with little or no flexibility. In Software - Defined Networks ( SDNs ),

Thermal Simulations, Open Boundary Conditions and Switches

Science.gov (United States)

Burnier, Yannis; Florio, Adrien; Kaczmarek, Olaf; Mazur, Lukas

2018-03-01

SU(N) gauge theories on compact spaces have a non-trivial vacuum structure characterized by a countable set of topological sectors and their topological charge. In lattice simulations, every topological sector needs to be explored a number of times which reflects its weight in the path integral. Current lattice simulations are impeded by the so-called freezing of the topological charge problem. As the continuum is approached, energy barriers between topological sectors become well defined and the simulations get trapped in a given sector. A possible way out was introduced by Lüscher and Schaefer using open boundary condition in the time extent. However, this solution cannot be used for thermal simulations, where the time direction is required to be periodic. In this proceedings, we present results obtained using open boundary conditions in space, at non-zero temperature. With these conditions, the topological charge is not quantized and the topological barriers are lifted. A downside of this method are the strong finite-size effects introduced by the boundary conditions. We also present some exploratory results which show how these conditions could be used on an algorithmic level to reshuffle the system and generate periodic configurations with non-zero topological charge.

Thermal Simulations, Open Boundary Conditions and Switches

Directory of Open Access Journals (Sweden)

Burnier Yannis

2018-01-01

Full Text Available SU(N gauge theories on compact spaces have a non-trivial vacuum structure characterized by a countable set of topological sectors and their topological charge. In lattice simulations, every topological sector needs to be explored a number of times which reflects its weight in the path integral. Current lattice simulations are impeded by the so-called freezing of the topological charge problem. As the continuum is approached, energy barriers between topological sectors become well defined and the simulations get trapped in a given sector. A possible way out was introduced by Lüscher and Schaefer using open boundary condition in the time extent. However, this solution cannot be used for thermal simulations, where the time direction is required to be periodic. In this proceedings, we present results obtained using open boundary conditions in space, at non-zero temperature. With these conditions, the topological charge is not quantized and the topological barriers are lifted. A downside of this method are the strong finite-size effects introduced by the boundary conditions. We also present some exploratory results which show how these conditions could be used on an algorithmic level to reshuffle the system and generate periodic configurations with non-zero topological charge.

Switching to sanitation: Understanding latrine adoption in a representative panel of rural Indian households.

Science.gov (United States)

Coffey, Diane; Spears, Dean; Vyas, Sangita

2017-09-01

Open defecation, which is still practiced by about a billion people worldwide, is one of the most compelling examples of how place influences health in developing countries. Efforts by governments and development organizations to address the world's remaining open defecation would be greatly supported by a better understanding of why some people adopt latrines and others do not. We analyze the 2005 and 2012 rounds of the India Human Development Survey (IHDS), a nationally representative panel of households in India, the country which is home to 60% of the people worldwide who defecate in the open. Among rural households that defecated in the open in 2005, we investigate what baseline properties and what changes over time are associated with switching to latrine use between 2005 and 2012. We find that households that are richer or better educated, that have certain demographic properties, or that improved their homes over this period were more likely to switch to using a latrine or toilet. However, each of these effect sizes is small; overall switching to latrine use from open defecation is low; and no ready household-level mechanisms are available for sanitation programs to widely influence these factors. Our research adds to a growing consensus in the literature that the social context should not be overlooked when trying to understand and bring about change in sanitation behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

A novel solid-state control system for the minimization of re-switching transient currents of induction motor

International Nuclear Information System (INIS)

Abro, M.R.; Larik, A.S.; Mahar, M.A.

2005-01-01

This work is an investigation into the minimizing re-closure transient currents of induction motors by activating NOVEL solid state control system switching at a matched condition. This emphasis is placed upon-circuit transition starting of cage motors, particularly star-delta switching. The initial study is carried out on single-phase induction motion. This system is capable of effective sensing re-closure of a switched off running single-phase induction motor. Further this scheme could be developed to give sequential delta closure of a switched off running three-phase induction motor during 1st cycles following the opening of the star mode. Consideration is also given to the possibility of using sensed re-closure to minimize transient whenever the supply to a running induction motor is briefly interrupted, irrespective of whether the interruption is by accident design. A brief study is made into the type of transient currents generated by opening the circuit of a running induction motor. The importance of the switching pattern for star-delta starting is explained and emphasized. (author)

Transient voltage sharing in series-coupled high voltage switches

Directory of Open Access Journals (Sweden)

Editorial Office

1992-07-01

Full Text Available For switching voltages in excess of the maximum blocking voltage of a switching element (for example, thyristor, MOSFET or bipolar transistor such elements are often coupled in series - and additional circuitry has to be provided to ensure equal voltage sharing. Between each such series element and system ground there is a certain parasitic capacitance that may draw a significant current during high-speed voltage transients. The "open" switch is modelled as a ladder network. Analy­sis reveals an exponential progression in the distribution of the applied voltage across the elements. Overstressing thus oc­curs in some of the elements at levels of the total voltage that are significantly below the design value. This difficulty is overcome by grading the voltage sharing circuitry, coupled in parallel with each element, in a prescribed manner, as set out here.

Influence of oxygen doping on resistive-switching characteristic of a-Si/c-Si device

Science.gov (United States)

Zhang, Jiahua; Chen, Da; Huang, Shihua

2017-12-01

The influence of oxygen doping on resistive-switching characteristics of Ag/a-Si/p+-c-Si device was investigated. By oxygen doping in the growth process of amorphous silicon, the device resistive-switching performances, such as the ON/OFF resistance ratios, yield and stability were improved, which may be ascribed to the significant reduction of defect density because of oxygen incorporation. The device I-V characteristics are strongly dependent on the oxygen doping concentration. As the oxygen doping concentration increases, the Si-rich device gradually transforms to an oxygen-rich device, and the device yield, switching characteristics, and stability may be improved for silver/oxygen-doped a-Si/p+-c-Si device. Finally, the device resistive-switching mechanism was analyzed. Project supported by the Zhejiang Provincial Natural Science Foundation of China (No. LY17F040001), the Open Project Program of Surface Physics Laboratory (National Key Laboratory) of Fudan University (No. KF2015_02), the Open Project Program of National Laboratory for Infrared Physics, Chinese Academy of Sciences (No. M201503), the Zhejiang Provincial Science and Technology Key Innovation Team (No. 2011R50012), and the Zhejiang Provincial Key Laboratory (No. 2013E10022).

Effect of the switching time on the performance of an adsorption chiller

International Nuclear Information System (INIS)

Hong, Sang Woo; Chung, Jae Dong; Kwon, Oh Kyung

2016-01-01

The switching time is an important operating condition that must be correctly anticipated for an effective adsorption cooling system. Before the adsorption (or desorption) process begins, time is required to cool down (or heat up) the bed temperature so that the bed pressure reaches the evaporator pressure (or condenser pressure). During the switching time, the supplied heat is reduced and pressure overload conditions can be avoided. The switching time cannot be estimated early on, and an improper switching time degrades the system performance. Thus, this study provides guideline with which to determine the required time to open this valve, i.e., the switching time, and carefully examines the thermo-physical behavior in the adsorption bed during this period. A two-dimensional numerical method with the composite sorbent of SWS-1L and a water pair is applied to a fin-tube type adsorption chiller. Three cases of no switching time, the optimal switching time and a double the optimal switching time are examined. The results show that no consideration of the switching time overestimates the performance of the adsorption cooling system in terms of the Coefficient of performance (COP) and the Specific cooling power (SCP). On the other hand, if the switching time exceeds the optimal value, the performance of the adsorption cooling system is also reduced compared to that when using the optimal switching time. The dependency of the optimal switching times on various design parameters, such as the fin pitch, fin height and heating temperature, is also examined.

Effect of the switching time on the performance of an adsorption chiller

Energy Technology Data Exchange (ETDEWEB)

Hong, Sang Woo; Chung, Jae Dong [Sejong University, Seoul (Korea, Republic of); Kwon, Oh Kyung [Korea Institute of Industrial Technology, Chonan (Korea, Republic of)

2016-05-15

The switching time is an important operating condition that must be correctly anticipated for an effective adsorption cooling system. Before the adsorption (or desorption) process begins, time is required to cool down (or heat up) the bed temperature so that the bed pressure reaches the evaporator pressure (or condenser pressure). During the switching time, the supplied heat is reduced and pressure overload conditions can be avoided. The switching time cannot be estimated early on, and an improper switching time degrades the system performance. Thus, this study provides guideline with which to determine the required time to open this valve, i.e., the switching time, and carefully examines the thermo-physical behavior in the adsorption bed during this period. A two-dimensional numerical method with the composite sorbent of SWS-1L and a water pair is applied to a fin-tube type adsorption chiller. Three cases of no switching time, the optimal switching time and a double the optimal switching time are examined. The results show that no consideration of the switching time overestimates the performance of the adsorption cooling system in terms of the Coefficient of performance (COP) and the Specific cooling power (SCP). On the other hand, if the switching time exceeds the optimal value, the performance of the adsorption cooling system is also reduced compared to that when using the optimal switching time. The dependency of the optimal switching times on various design parameters, such as the fin pitch, fin height and heating temperature, is also examined.

Energy reversible switching from amorphous metal based nanoelectromechanical switch

KAUST Repository

Mayet, Abdulilah M.; Smith, Casey; Hussain, Muhammad Mustafa

2013-01-01

We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young's modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young's modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

Energy reversible switching from amorphous metal based nanoelectromechanical switch

KAUST Repository

Mayet, Abdulilah M.

2013-08-01

We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young\\'s modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young\\'s modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

Optical switching based on the manipulation of microparticles in a colloidal liquid using strong scattering force

International Nuclear Information System (INIS)

Liu Jin; Liu Zheng-Qi; Feng Tian-Hua; Dai Qiao-Feng; Wu Li-Jun; Lan Sheng

2010-01-01

This paper demonstrates the realization of an optical switch by optically manipulating a large number of polystyrene spheres contained in a capillary. The strong scattering force exerted on polystyrene spheres with a large diameter of 4.3 μm is employed to realize the switching operation. A transparent window is opened for the signal light when the polystyrene spheres originally located at the beam centre are driven out of the beam region by the strong scattering force induced by the control light. The switching dynamics under different incident powers is investigated and compared with that observed in the optical switch based on the formation of optical matter. It is found that a large extinction ratio of ∼ 30 dB and fast switching-on and switching-off times can be achieved in this type of switch. (classical areas of phenomenology)

Long-term efficacy and tolerability of quetiapine in patients with schizophrenia who switched from other antipsychotics because of inadequate therapeutic response-a prospective open-label study.

Science.gov (United States)

Hashimoto, Naoki; Toyomaki, Atsuhito; Honda, Minoru; Miyano, Satoru; Nitta, Nobuyuki; Sawayama, Hiroyuki; Sugawara, Yasufumi; Uemura, Keiichi; Tsukamoto, Noriko; Koyama, Tsukasa; Kusumi, Ichiro

2015-01-01

While the frequency and importance of antipsychotic switching in patients with schizophrenia, there is insufficient evidence with regard to switching strategy. Quetiapine is one of the drugs of choice for switch because of its unique receptor profile. However, there were no data on the long-term clinical and neurocognitive effect of quetiapine in patients who had responded inadequately to prior antipsychotics. The purpose of this study is to examine the long-term efficacy and tolerability of quetiapine in patients with schizophrenia who switched from other antipsychotics because of inadequate therapeutic response. We hypothesized that quetiapine would show long-term effectiveness in broad symptom dimensions including negative and neurocognitive symptoms while having good tolerability. Twenty-nine subjects with schizophrenia who did not respond to their current monotherapy of antipsychotic or who could not tolerate the treatment were switched to quetiapine and assessed at baseline and at 3, 6, and 12 months. The outcome measures included the brief assessment of cognition in schizophrenia (BACS), the Positive and Negative Syndrome Scale (PANSS), the Clinical Global Impressions Scale (CGI), the Schizophrenia Quality of Life Scale Japanese version (JSQLS), the Athens Insomnia Scale (AIS), and the Drug Attitude Inventory with 30 items (DAI-30). The Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS), HbA1c, prolactin (PRL), and body weight were also evaluated. Statistically significant improvements were observed in all subscores of the PANSS, the GAF, and the symptoms and side effects subscale of the JSQLS, the DIEPSS, the AIS, and the PRL level, and nearly significant improvements were observed in the DAI-30. Quetiapine monotherapy was associated with significant improvement in the verbal memory test, even after controlling for the practice effect. Although quetiapine was well tolerated, three subjects dropped out because of the worsening of the psychotic symptoms and

Beam steering for circular switched parasitic arrays using a combinational approach

CSIR Research Space (South Africa)

Mofolo, ROM

2011-09-01

Full Text Available In this paper, the authors present a method of electronic beam steering for circular switched parasitic array (SPA) antennas. In circular SPA antennas, one achieves azimuth beam steering by open-circuiting and short-circuiting different parasitic...

A packet switched communications system for GRO

Science.gov (United States)

Husain, Shabu; Yang, Wen-Hsing; Vadlamudi, Rani; Valenti, Joseph

1993-11-01

This paper describes the packet switched Instrumenters Communication System (ICS) that was developed for the Command Management Facility at GSFC to support the Gamma Ray Observatory (GRO) spacecraft. The GRO ICS serves as a vital science data acquisition link to the GRO scientists to initiate commands for their spacecraft instruments. The system is ready to send and receive messages at any time, 24 hours a day and seven days a week. The system is based on X.25 and the International Standard Organization's (ISO) 7-layer Open Systems Interconnection (OSI) protocol model and has client and server components. The components of the GRO ICS are discussed along with how the Communications Subsystem for Interconnection (CSFI) and Network Control Program Packet Switching Interface (NPSI) software are used in the system.

Bilingual Voicing: A Study of Code-Switching in the Reported Speech of Finnish Immigrants in Estonia

Science.gov (United States)

Frick, Maria; Riionheimo, Helka

2013-01-01

Through a conversation analytic investigation of Finnish-Estonian bilingual (direct) reported speech (i.e., voicing) by Finns who live in Estonia, this study shows how code-switching is used as a double contextualization device. The code-switched voicings are shaped by the on-going interactional situation, serving its needs by opening up a context…

Pseudospark switches

International Nuclear Information System (INIS)

Billault, P.; Riege, H.; Gulik, M. van; Boggasch, E.; Frank, K.

1987-01-01

The pseudospark discharge is bound to a geometrical structure which is particularly well suited for switching high currents and voltages at high power levels. This type of discharge offers the potential for improvement in essentially all areas of switching operation: peak current and current density, current rise, stand-off voltage, reverse current capability, cathode life, and forward drop. The first pseudospark switch was built at CERN at 1981. Since then, the basic switching characteristics of pseudospark chambers have been studied in detail. The main feature of a pseudospark switch is the confinement of the discharge plasma to the device axis. The current transition to the hollow electrodes is spread over a rather large surface area. Another essential feature is the easy and precise triggering of the pseudospark switch from the interior of the hollow electrodes, relatively far from the main discharge gap. Nanosecond delay and jitter values can be achieved with trigger energies of less than 0.1 mJ, although cathode heating is not required. Pseudospark gaps may cover a wide range of high-voltage, high-current, and high-pulse-power switching at repetition rates of many kilohertz. This report reviews the basic researh on pseudospark switches which has been going on at CERN. So far, applications have been developed in the range of thyratron-like medium-power switches at typically 20 to 40 kV and 0.5 to 10 kA. High-current pseudospark switches have been built for a high-power 20 kJ pulse generator which is being used for long-term tests of plasma lenses developed for the future CERN Antiproton Collector (ACOL). The high-current switches have operated for several hundred thousand shots, with 20 to 50 ns jitter at 16 kV charging voltage and more than 100 kA peak current amplitude. (orig.)

Synchronization Between Two Different Switched Chaotic Systems By Switching Control

Directory of Open Access Journals (Sweden)

Du Li Ming

2016-01-01

Full Text Available This paper is concerned with the synchronization problem of two different switched chaotic systems, considering the general case that the master-slave switched chaotic systems have uncertainties. Two basic problems are considered: one is projective synchronization of switched chaotic systems under arbitrary switching; the other is projective synchronization of switched chaotic systems by design of switching when synchronization cannot achieved by using any subsystems alone. For the two problems, common Lyapunov function method and multiple Lyapunov function method are used respectively, an adaptive control scheme has been presented, some sufficient synchronization conditions are attainted, and the switching signal is designed. Finally, the numerical simulation is provide to show the effectiveness of our method.

Exciter switch

Science.gov (United States)

Mcpeak, W. L.

1975-01-01

A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.

Nudging Leads Consumers In Colorado To Shop But Not Switch ACA Marketplace Plans.

Science.gov (United States)

Marzilli Ericson, Keith M; Kingsdale, Jon; Layton, Tim; Sacarny, Adam

2017-02-01

The Affordable Care Act (ACA) dramatically expanded the use of regulated marketplaces in health insurance, but consumers often fail to shop for plans during open enrollment periods. Typically these consumers are automatically reenrolled in their old plans, which potentially exposes them to unexpected increases in their insurance premiums and cost sharing. We conducted a randomized intervention to encourage enrollees in an ACA Marketplace to shop for plans. We tested the effect of letters and e-mails with personalized information about the savings on insurance premiums that they could realize from switching plans and the effect of generic communications that simply emphasized the possibility of saving. The personalized and generic messages both increased shopping on the Marketplace's website by 23 percent, but neither type of message had a significant effect on plan switching. These findings show that simple "nudges" with even generic information can promote shopping in health insurance marketplaces, but whether they can lead to switching remains an open question. Project HOPE—The People-to-People Health Foundation, Inc.

A Switch Is Not a Switch: Syntactically-Driven Bilingual Language Control

Science.gov (United States)

Gollan, Tamar H.; Goldrick, Matthew

2018-01-01

The current study investigated the possibility that language switches could be relatively automatically triggered by context. "Single-word switches," in which bilinguals switched languages on a single word in midsentence and then immediately switched back, were contrasted with more complete "whole-language switches," in which…

Switching Phenomena in a System with No Switches

Science.gov (United States)

Preis, Tobias; Stanley, H. Eugene

2010-02-01

It is widely believed that switching phenomena require switches, but this is actually not true. For an intriguing variety of switching phenomena in nature, the underlying complex system abruptly changes from one state to another in a highly discontinuous fashion. For example, financial market fluctuations are characterized by many abrupt switchings creating increasing trends ("bubble formation") and decreasing trends ("financial collapse"). Such switching occurs on time scales ranging from macroscopic bubbles persisting for hundreds of days to microscopic bubbles persisting only for a few seconds. We analyze a database containing 13,991,275 German DAX Future transactions recorded with a time resolution of 10 msec. For comparison, a database providing 2,592,531 of all S&P500 daily closing prices is used. We ask whether these ubiquitous switching phenomena have quantifiable features independent of the time horizon studied. We find striking scale-free behavior of the volatility after each switching occurs. We interpret our findings as being consistent with time-dependent collective behavior of financial market participants. We test the possible universality of our result by performing a parallel analysis of fluctuations in transaction volume and time intervals between trades. We show that these financial market switching processes have properties similar to those of phase transitions. We suggest that the well-known catastrophic bubbles that occur on large time scales—such as the most recent financial crisis—are no outliers but single dramatic representatives caused by the switching between upward and downward trends on time scales varying over nine orders of magnitude from very large (≈102 days) down to very small (≈10 ms).

Augmented switching linear dynamical system model for gas concentration estimation with MOX sensors in an open sampling system.

Science.gov (United States)

Di Lello, Enrico; Trincavelli, Marco; Bruyninckx, Herman; De Laet, Tinne

2014-07-11

In this paper, we introduce a Bayesian time series model approach for gas concentration estimation using Metal Oxide (MOX) sensors in Open Sampling System (OSS). Our approach focuses on the compensation of the slow response of MOX sensors, while concurrently solving the problem of estimating the gas concentration in OSS. The proposed Augmented Switching Linear System model allows to include all the sources of uncertainty arising at each step of the problem in a single coherent probabilistic formulation. In particular, the problem of detecting on-line the current sensor dynamical regime and estimating the underlying gas concentration under environmental disturbances and noisy measurements is formulated and solved as a statistical inference problem. Our model improves, with respect to the state of the art, where system modeling approaches have been already introduced, but only provided an indirect relative measures proportional to the gas concentration and the problem of modeling uncertainty was ignored. Our approach is validated experimentally and the performances in terms of speed of and quality of the gas concentration estimation are compared with the ones obtained using a photo-ionization detector.

Methodology, Measurement and Analysis of Flow Table Update Characteristics in Hardware OpenFlow Switches

KAUST Repository

Kuźniar, Maciej; Pereší ni, Peter; Kostić, Dejan; Canini, Marco

2018-01-01

and performance characteristics is essential for ensuring successful and safe deployments.We propose a systematic methodology for SDN switch performance analysis and devise a series of experiments based on this methodology. The methodology relies on sending a

A 0.2 V Micro-Electromechanical Switch Enabled by a Phase Transition.

Science.gov (United States)

Dong, Kaichen; Choe, Hwan Sung; Wang, Xi; Liu, Huili; Saha, Bivas; Ko, Changhyun; Deng, Yang; Tom, Kyle B; Lou, Shuai; Wang, Letian; Grigoropoulos, Costas P; You, Zheng; Yao, Jie; Wu, Junqiao

2018-04-01

Micro-electromechanical (MEM) switches, with advantages such as quasi-zero leakage current, emerge as attractive candidates for overcoming the physical limits of complementary metal-oxide semiconductor (CMOS) devices. To practically integrate MEM switches into CMOS circuits, two major challenges must be addressed: sub 1 V operating voltage to match the voltage levels in current circuit systems and being able to deliver at least millions of operating cycles. However, existing sub 1 V mechanical switches are mostly subject to significant body bias and/or limited lifetimes, thus failing to meet both limitations simultaneously. Here 0.2 V MEM switching devices with ≳10 6 safe operating cycles in ambient air are reported, which achieve the lowest operating voltage in mechanical switches without body bias reported to date. The ultralow operating voltage is mainly enabled by the abrupt phase transition of nanolayered vanadium dioxide (VO 2 ) slightly above room temperature. The phase-transition MEM switches open possibilities for sub 1 V hybrid integrated devices/circuits/systems, as well as ultralow power consumption sensors for Internet of Things applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The influence of electrical resistivity, magnetic field strength, boundary conditions, and injection conditions on the behavior of the magnetically injected plasma in the PBFA-II opening switch

International Nuclear Information System (INIS)

Watrous, J.J.; Frese, M.H.

1993-01-01

The Plasma Opening Switch used on PBFA-II uses a source plasma which is injected into the inter-electrode gap along the field lines of a modest-strength applied poloidal magnetic field. The distribution of this plasma within the gap plays an important role in the behavior of the switch. Knowledge of this distribution is critical for performing relevant switch calculations and for interpreting experimental data. In the work reported here, the influence on that distribution of the plasma electrical resistivity, the applied magnetic field strength, and the boundary and injection conditions have been investigated with the 2 1/2-dimensional magnetohydrodynamics simulation code, MACH2. The injected plasma has density in the 10 14 cm -3 range and temperature in the several eV range. In this parameter regime, the classical collision time scale is on the order of 10 ns, which, when compared to the 100 ns time scale of the inflowing plasma, means that the plasma is classically collisionless. However, mechanisms other than classical collisions are likely to contribute to electrical resistivity. The authors have investigated the effect of an anomalous resistivity which scales with the plasma frequency, varying the scaling from the electron plasma frequency to the ion plasma frequency. They will compare these results with results based on the assumption of an ideal plasma, and discuss other anomalous resistivity models

Body weight - Open TG-GATEs | LSDB Archive [Life Science Database Archive metadata

Lifescience Database Archive (English)

Full Text Available switchLanguage; BLAST Search Image Search Home About Archive Update History Data ...le URL: ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/open_tggates_body_...atabase Description Download License Update History of This Database Site Policy | Contact Us Body weight - Open TG-GATEs | LSDB Archive ...

EDITORIAL: Molecular switches at surfaces Molecular switches at surfaces

Science.gov (United States)

Weinelt, Martin; von Oppen, Felix

2012-10-01

In nature, molecules exploit interaction with their environment to realize complex functionalities on the nanometer length scale. Physical, chemical and/or biological specificity is frequently achieved by the switching of molecules between microscopically different states. Paradigmatic examples are the energy production in proton pumps of bacteria or the signal conversion in human vision, which rely on switching molecules between different configurations or conformations by external stimuli. The remarkable reproducibility and unparalleled fatigue resistance of these natural processes makes it highly desirable to emulate nature and develop artificial systems with molecular functionalities. A promising avenue towards this goal is to anchor the molecular switches at surfaces, offering new pathways to control their functional properties, to apply electrical contacts, or to integrate switches into larger systems. Anchoring at surfaces allows one to access the full range from individual molecular switches to self-assembled monolayers of well-defined geometry and to customize the coupling between molecules and substrate or between adsorbed molecules. Progress in this field requires both synthesis and preparation of appropriate molecular systems and control over suitable external stimuli, such as light, heat, or electrical currents. To optimize switching and generate function, it is essential to unravel the geometric structure, the electronic properties and the dynamic interactions of the molecular switches on surfaces. This special section, Molecular Switches at Surfaces, collects 17 contributions describing different aspects of this research field. They analyze elementary processes, both in single molecules and in ensembles of molecules, which involve molecular switching and concomitant changes of optical, electronic, or magnetic properties. Two topical reviews summarize the current status, including both challenges and achievements in the field of molecular switches on

Plasma flow switch characterization for the Los Alamos Foil Implosion Project

International Nuclear Information System (INIS)

Bowers, R.L.; Brownell, J.H.; Greene, A.E.; Peterson, D.L.

1990-01-01

The next system design under consideration for the Los Alamos Foil Implosion Project is projected to deliver tens of mega-amperes of electrical current produced by high-explosive driven flux compression generators on a time scale of about one microsecond to a load foil. The use of such generators, with time scales of order several tenths of a millisecond, leads to considerable pulse shaping problems. Previously it was noted that a commutating switch might serve as an efficient alternative to a closing switch in transferring current from a coaxial transmission line to a cylindrically imploding load. Research at the Air Force Weapons Laboratory (AFWL) has met with considerable success in efficiently transferring currents of order 10 MA to an imploding liner using the plasma flow switch concept (PFS). Besides efficiently transferring current, the plasma flow switch protects the load region from high voltages generated by an opening switch until the current is present to provide magnetic insulation. For these reasons, a PFS is being investigated as the final pulse shaping step in the design. A series of capacitor bank experiments is also being fielded to help investigate physics issues and to benchmark the codes

No switch to coal-based feedstocks until 2000

Energy Technology Data Exchange (ETDEWEB)

1977-06-10

This is a resume of a paper ''Organics for the 1980s-petrochemicals or coal chemicals'' by S. P. S. Andrew. There will be no significant switch from petrochemicals to coal-based chemicals worldwide until well into the 21st century, when synthetic gasoline could be made in the U. S. from open-cast coal. Processes are being developed for converting coal to gasoline, ethylene, and ammonia.

Investigation of electrically exploded large area foil for current switching

International Nuclear Information System (INIS)

Chernyshev, V.K.; Boyko, A.M.; Kostyukov, V.N.; Kuzyaev, A.I.; Kulagin, A.A.; Mamyshev, V.I.; Mezhevov, A.B.; Nechaev, A.I.; Petrukhin, A.A.; Protasov, M.S.; Shevtsov, V.I.; Yakubov, V.B.

1990-01-01

The possibility of microsecond ∼40 MA current switching from EMG into a quasiconstant inductive load by an electrically exploded foil is investigated. The copper foil of large area, S ∼ 10 4 cm 2 , was placed between thin-walled insulators into a coaxial transmission line (TL). This paper shows a conceptual device scheme. To feed a foil opening switch (FOS), a disc explosive magnetic generator (DEMG) with 20 μs current rise time was employed. An inductive coaxial load was connected to a FOS at a moment, that was close to the foil vaporization start by means of an axisymmetric explosive current commutator (ECC)

Optimal control of switching time in switched stochastic systems with multi-switching times and different costs

Science.gov (United States)

Liu, Xiaomei; Li, Shengtao; Zhang, Kanjian

2017-08-01

In this paper, we solve an optimal control problem for a class of time-invariant switched stochastic systems with multi-switching times, where the objective is to minimise a cost functional with different costs defined on the states. In particular, we focus on problems in which a pre-specified sequence of active subsystems is given and the switching times are the only control variables. Based on the calculus of variation, we derive the gradient of the cost functional with respect to the switching times on an especially simple form, which can be directly used in gradient descent algorithms to locate the optimal switching instants. Finally, a numerical example is given, highlighting the validity of the proposed methodology.

Assumption or Fact? Line-to-Neutral Voltage Expression in an Unbalanced 3-Phase Circuit during Inverter Switching

Science.gov (United States)

Masrur, M. A.

2009-01-01

This paper discusses the situation in a 3-phase motor or any other 3-phase system operating under unbalanced operating conditions caused by an open fault in an inverter switch. A dc voltage source is assumed as the input to the inverter, and under faulty conditions of the inverter switch, the actual voltage applied between the line to neutral…

Comparative effectiveness of switching paroxetine formulation for treatment of major depressive disorder: an open-label multicenter study

Directory of Open Access Journals (Sweden)

Otsubo T

2018-04-01

Full Text Available Tempei Otsubo,1 Yoshinori Watanabe,2,3 Seiji Hongo,3 Mikichika Inoue,4 Kimiko Akimoto,4 Ken Murakami,5 Ryutaro Takahashi,6 Toshiaki Kikuchi7 1Department of Psychiatry, Tokyo Women’s Medical University Medical Center East, Tokyo, Japan; 2Himorogi Psychiatric Institute, Tokyo, Japan; 3Nanko Clinic of Psychiatry, Shirakawa, Japan; 4Ikebukuro Internal Medicine, Tokyo, Japan; 5Murakami Hospital, Tokyo, Japan; 6Takahashi Clinic, Tokyo, Japan; 7Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan Aim: To assess the effectiveness and safety of switching the antidepressant formulation from immediate-release (IR to controlled-release (CR paroxetine in patients with major depressive disorder (MDD. Patients and methods: A total of 113 outpatients with MDD diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, and treated with a stable dose of IR paroxetine for at least 6 months were enrolled. Patients were then switched to CR paroxetine for 8 weeks. Effectiveness was evaluated by scores on the Himorogi Self-Rating Depression/Anxiety Scales (HSDS/HSAS and the Clinical Global Impression – Severity (CGI-S. Safety was evaluated based on the reported adverse drug reactions (ADRs. Medication satisfaction and preference were assessed based on questionnaire responses using Likert-type scales. Results: The overall patient HSDS/HSAS scores significantly improved after switching from IR to CR paroxetine (P<0.001. Furthermore, CR paroxetine was superior to IR paroxetine (P<0.001 according to the results of the CGI-S evaluation. ADRs were experienced by 14 (12.4% patients, including dry mouth, nausea/vomiting, somnolence/drowsiness, and wakefulness/arousal during sleep. Satisfaction and preference for paroxetine improved after switching to the CR formulation (P<0.001; chi-square test. Conclusion: These results suggest that switching the treatment from IR to CR paroxetine could

Soft controller switching technique to minimize the torque and current pulsations of a SCIM during its reswitching

International Nuclear Information System (INIS)

Larik, A.S.

2010-01-01

The direct-on-line starting of induction motor draws heavy current and to limit this Inrush current to a safe level normally a star-delta switch is used. However, the switching over from star to delta causes over current transients and this leads to torque pulsations. Therefore, in this paper the current and torque pulsations developed during the switching process are focused and a soft-switched controller is devised to minimize the re-closure transient currents and torque pulsations during star-delta switching of induction motor. The designed system can readily handles the sensing of favorable conditions of re closure of a switched-off running induction motor and it minimizes the inrush current and hence the pulsations of torque of all types of induction motors, whether, single-phase or three phase. An investigation is made into the transient currents and pulsation torques generated due to opening the circuit of a running induction motor and the switching pattern of star-delta switching. The re-switching control scheme for the induction motor is practically tested in the laboratory with and without soft controller. (author)

Continuing studies of plasma erosion switches for power conditioning on multiterawatt pulsed power accelerators

International Nuclear Information System (INIS)

Stringfield, R.; Gilman, C.; James, G.; Peters, T.; Sincerny, P.; Wong, S.

1983-01-01

Recent PITHON experiments with plasma erosion switches (PES) have extended the range of operation of the switches by about 50 percent, in terms of closed time and charge passing through the switch. The quantity of charge passed through the switch has been increased to as much as 35 mC. Currents as large as 1 MA and voltages as great as 1.8 MV have been switched off to be diverted to a downstream load. The impedance of the erosion switch can be described as having three stages: 1) essentially zero impedance, 2) a transitional opening phase, and 3) an impedance which is very large (greater than 5 Ω) in comparison with the subohm downstream load. Current diagnostics, consisting of Rogowski coils and segmented shunts, have been successfully developed to monitor the current which propagates to the load region. These monitors have measured rise times as short as 38 ns and slew rates as great as 10 14 A/s at the load. With wire array loads, the pulse conditioning of the switch has been observed to reduce the magnitude of the current losses in the feed which are present when no switch is used. Correlations have been made between the switch closed time, voltage, current, and power with the feed inductance and the generator power injected into the magnetic insulated transmission line (MITL)

Traction Inverter Open Switch Fault Diagnosis Based on Choi–Williams Distribution Spectral Kurtosis and Wavelet-Packet Energy Shannon Entropy

Directory of Open Access Journals (Sweden)

Shuangshuang Lin

2017-09-01

Full Text Available In this paper, a new approach for fault detection and location of open switch faults in the closed-loop inverter fed vector controlled drives of Electric Multiple Units is proposed. Spectral kurtosis (SK based on Choi–Williams distribution (CWD as a statistical tool can effectively indicate the presence of transients and locations in the frequency domain. Wavelet-packet energy Shannon entropy (WPESE is appropriate for the transient changes detection of complex non-linear and non-stationary signals. Based on the analyses of currents in normal and fault conditions, SK based on CWD and WPESE are combined with the DC component method. SK based on CWD and WPESE are used for the fault detection, and the DC component method is used for the fault localization. This approach can diagnose the specific locations of faulty Insulated Gate Bipolar Transistors (IGBTs with high accuracy, and it requires no additional devices. Experiments on the RT-LAB platform are carried out and the experimental results verify the feasibility and effectiveness of the diagnosis method.

Digital switched hydraulics

Science.gov (United States)

Pan, Min; Plummer, Andrew

2018-06-01

This paper reviews recent developments in digital switched hydraulics particularly the switched inertance hydraulic systems (SIHSs). The performance of SIHSs is presented in brief with a discussion of several possible configurations and control strategies. The soft switching technology and high-speed switching valve design techniques are discussed. Challenges and recommendations are given based on the current research achievements.

Enhancement of resistive switching properties in Al2O3 bilayer-based atomic switches: multilevel resistive switching

Science.gov (United States)

Vishwanath, Sujaya Kumar; Woo, Hyunsuk; Jeon, Sanghun

2018-06-01

Atomic switches are considered to be building blocks for future non-volatile data storage and internet of things. However, obtaining device structures capable of ultrahigh density data storage, high endurance, and long data retention, and more importantly, understanding the switching mechanisms are still a challenge for atomic switches. Here, we achieved improved resistive switching performance in a bilayer structure containing aluminum oxide, with an oxygen-deficient oxide as the top switching layer and stoichiometric oxide as the bottom switching layer, using atomic layer deposition. This bilayer device showed a high on/off ratio (105) with better endurance (∼2000 cycles) and longer data retention (104 s) than single-oxide layers. In addition, depending on the compliance current, the bilayer device could be operated in four different resistance states. Furthermore, the depth profiles of the hourglass-shaped conductive filament of the bilayer device was observed by conductive atomic force microscopy.

Intentional preparation of auditory attention-switches: Explicit cueing and sequential switch-predictability.

Science.gov (United States)

Seibold, Julia C; Nolden, Sophie; Oberem, Josefa; Fels, Janina; Koch, Iring

2018-06-01

In an auditory attention-switching paradigm, participants heard two simultaneously spoken number-words, each presented to one ear, and decided whether the target number was smaller or larger than 5 by pressing a left or right key. An instructional cue in each trial indicated which feature had to be used to identify the target number (e.g., female voice). Auditory attention-switch costs were found when this feature changed compared to when it repeated in two consecutive trials. Earlier studies employing this paradigm showed mixed results when they examined whether such cued auditory attention-switches can be prepared actively during the cue-stimulus interval. This study systematically assessed which preconditions are necessary for the advance preparation of auditory attention-switches. Three experiments were conducted that controlled for cue-repetition benefits, modality switches between cue and stimuli, as well as for predictability of the switch-sequence. Only in the third experiment, in which predictability for an attention-switch was maximal due to a pre-instructed switch-sequence and predictable stimulus onsets, active switch-specific preparation was found. These results suggest that the cognitive system can prepare auditory attention-switches, and this preparation seems to be triggered primarily by the memorised switching-sequence and valid expectations about the time of target onset.

Cognitive processes and neural basis of language switching: proposal of a new model.

Science.gov (United States)

Moritz-Gasser, Sylvie; Duffau, Hugues

2009-12-09

Although studies on bilingualism are abundant, cognitive processes and neural foundations of language switching received less attention. The aim of our study is to provide new insights to this still open question: do dedicated region(s) for language switching exist or is this function underlain by a distributed circuit of interconnected brain areas, part of a more general cognitive system? On the basis of recent behavioral, neuroimaging, and brain stimulation studies, we propose an original 'hodological' model of language switching. This process might be subserved by a large-scale cortico-subcortical network, with an executive system (prefrontal cortex, anterior cingulum, caudate nucleus) controlling a more dedicated language subcircuit, which involves postero-temporal areas, supramarginal and angular gyri, Broca's area, and the superior longitudinal fasciculus.

Reduced Fluorescent Protein Switching Fatigue by Binding-Induced Emissive State Stabilization

Directory of Open Access Journals (Sweden)

Thijs Roebroek

2017-09-01

Full Text Available Reversibly switchable fluorescent proteins (RSFPs enable advanced fluorescence imaging, though the performance of this imaging crucially depends on the properties of the labels. We report on the use of an existing small binding peptide, named Enhancer, to modulate the spectroscopic properties of the recently developed rsGreen series of RSFPs. Fusion constructs of Enhancer with rsGreen1 and rsGreenF revealed an increased molecular brightness and pH stability, although expression in living E. coli or HeLa cells resulted in a decrease of the overall emission. Surprisingly, Enhancer binding also increased off-switching speed and resistance to switching fatigue. Further investigation suggested that the RSFPs can interconvert between fast- and slow-switching emissive states, with the overall protein population gradually converting to the slow-switching state through irradiation. The Enhancer modulates the spectroscopic properties of both states, but also preferentially stabilizes the fast-switching state, supporting the increased fatigue resistance. This work demonstrates how the photo-physical properties of RSFPs can be influenced by their binding to other small proteins, which opens up new horizons for applications that may require such modulation. Furthermore, we provide new insights into the photoswitching kinetics that should be of general consideration when developing new RSFPs with improved or different photochromic properties.

Note: Switching crosstalk on and off in Kelvin probe force microscopy

International Nuclear Information System (INIS)

Polak, Leo; Wijngaarden, Rinke J.; Man, Sven de

2014-01-01

In Kelvin Probe Force Microscopy (KPFM) electronic crosstalk can occur between the excitation signal and probe deflection signal. Here, we demonstrate how a small modification to our commercial instrument enables us to literally switch the crosstalk on and off. We study in detail the effect of crosstalk on open-loop KPFM and compare with closed-loop KPFM. We measure the pure crosstalk signal and verify that we can correct for it in the data-processing required for open-loop KPFM. We also demonstrate that open-loop KPFM results are independent of the frequency and amplitude of the excitation signal, provided that the influence of crosstalk has been eliminated

Temperature dependent electron transport and rate coefficient studies for e-beam-sustained diffuse gas discharge switching

International Nuclear Information System (INIS)

Carter, J.G.; Hunter, S.R.; Christophorou, L.G.

1987-01-01

Measurements of the electron drift velocity, w, attachment coefficient, eta/N/sub a/, and ionization coefficient, α/N, have been made in C 2 F 6 /Ar and C 2 F 6 /CH 4 gas mixtures at gas temperatures, T, of 300 and 500 0 K over the concentration range of 0.1 to 100% of the C 2 F 6 . These measurements are useful for modeling the expected behavior of repetitively operated electron-beam sustained diffuse gas discharge opening switches where gas temperatures within the switch are anticipated to rise several hundred degrees during switch operation

Combustion mode switching with a turbocharged/supercharged engine

Science.gov (United States)

Mond, Alan; Jiang, Li

2015-09-22

A method for switching between low- and high-dilution combustion modes in an internal combustion engine having an intake passage with an exhaust-driven turbocharger, a crankshaft-driven positive displacement supercharger downstream of the turbocharger and having variable boost controllable with a supercharger bypass valve, and a throttle valve downstream of the supercharger. The current combustion mode and mass air flow are determined. A switch to the target combustion mode is commanded when an operating condition falls within a range of predetermined operating conditions. A target mass air flow to achieve a target air-fuel ratio corresponding to the current operating condition and the target combustion mode is determined. The degree of opening of the supercharger bypass valve and the throttle valve are controlled to achieve the target mass air flow. The amount of residual exhaust gas is manipulated.

Demonstration of Ultra-Fast Switching in Nano metallic Resistive Switching Memory Devices

International Nuclear Information System (INIS)

Yang, Y.

2016-01-01

Interdependency of switching voltage and time creates a dilemma/obstacle for most resistive switching memories, which indicates low switching voltage and ultra-fast switching time cannot be simultaneously achieved. In this paper, an ultra-fast (sub-100 ns) yet low switching voltage resistive switching memory device (“nano metallic ReRAM”) was demonstrated. Experimental switching voltage is found independent of pulse width (intrinsic device property) when the pulse is long but shows abrupt time dependence (“cliff”) as pulse width approaches characteristic RC time of memory device (extrinsic device property). Both experiment and simulation show that the onset of cliff behavior is dependent on physical device size and parasitic resistance, which is expected to diminish as technology nodes shrink down. We believe this study provides solid evidence that nano metallic resistive switching memory can be reliably operated at low voltage and ultra-fast regime, thus beneficial to future memory technology.

DESAIN DAN IMPLEMENTSI SOFT SWITCHING BOOST KONVERTER DENGAN SIMPLE AUXILLARY RESONANT SWITCH (SARC

Directory of Open Access Journals (Sweden)

Dimas Bagus Saputra

2017-01-01

Full Text Available Boost konverter merupakan penaik tegangan DC ke tegangan DC yang mempunyai tegangan output yang lebih tinggi dibanding inputnya. Penggunaan boost konverter diera modern semakin meningkat dan dibuat dengan dimensi yang lebih kecil, berat yang lebih ringan dan efisiensi yang lebih tinggi dibanding dengan boost konverter generasi terdahulu. Tetapi rugi-rugi periodik saat on/off meningkat. Untuk meraih kriteria tersebut, teknik hard switching boost konverter berevolusi menjadi teknik soft switching dengan menambah rangkaian simple auxiliary resonant circuit (SARC. Karena penambahan rangkaian SARC tersebut konverter bekerja pada kondisi zero-voltage switching switch (ZVS dan zero current switch (ZCS, sehingga saklar semikonduktor tidak bekerja secara hard switching lagi. Pada penelitian ini akan di desain dan diimplementaskan soft switching boost konverter dengan SARC. Kelebihan dari soft switching boost konverter dengan SARC adalah mempunyai efisiensi yang lebih tinggi dibanding dengan boost konverter konventional. Dari hasil implementasi menunjukkan konverter yang diajukan telah meraih zero voltage switch (ZVS. Sehingga boost konverter zero voltage switch (ZVS bisa diaplikasikan pada sistem power suplay yang membutuhkan efisiensi energi yang tinggi terutama pada daya yang tinggi.

Forget about switching keyboard layouts with the "Compose Key"

CERN Multimedia

CERN. Geneva

2018-01-01

Growing up with a Spanish keyboard was not an easy childhood (using Shift+7 (/) to search in vim, or having to type AltGr+[ to actually have an opening bracket), so at some point in my life I switched to an American keyboard. At the beginning I was happy switching layouts to either do some coding or talk to my mum (I am not a fan of the classical excuse "sorry for my typos, I don't have the 'ñ' in my keyboard"). Things got much worse when I started to need French characters (ç, è) to interact with some services at CERN, or some Slovak letters (č, đ) to talk to Robert, my Slovak colleague . Then I discovered the Compose Key and my life has been different ever since.

All-fiber optical mode switching based on cascaded mode selective couplers for short-reach MDM networks

Science.gov (United States)

Ren, Fang; Li, Juhao; Wu, Zhongying; Yu, Jinyi; Mo, Qi; Wang, Jianping; He, Yongqi; Chen, Zhangyuan; Li, Zhengbin

2017-04-01

We propose and experimentally demonstrate an all-fiber optical mode switching structure supporting independent switching, exchanging, adding, and dropping functionalities in which each mode can be switched individually. The mode switching structure consists of cascaded mode selective couplers (MSCs) capable of exciting and selecting specific higher order modes in few-mode fibers with high efficiency and one multiport optical switch routing the independent spatial modes to their destinations. The data carried on three different spatial modes can be switched, exchanged, added, and dropped through this all-fiber structure. For this experimental demonstration, optical on-off-keying (OOK) signals at 10-Gb/s carried on three spatial modes are successfully processed with open and clear eye diagrams. The mode switch exhibits power penalties of less than 3.1 dB after through operation, less than 2.7 dB after exchange operation, less than 2.8 dB after switching operation, and less than 1.6 dB after mode adding and dropping operations at the bit-error rate (BER) of 10-3, while all three channels carried on three spatial modes are simultaneously routed. The proposed structure, compatible with current optical switching networks based on single-mode fibers, can potentially be used to expand the switching scalability in advanced and flexible short-reach mode-division multiplexing-based networks.

Saturated Switching Systems

CERN Document Server

Benzaouia, Abdellah

2012-01-01

Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

Light-activated resistance switching in SiOx RRAM devices

Science.gov (United States)

Mehonic, A.; Gerard, T.; Kenyon, A. J.

2017-12-01

We report a study of light-activated resistance switching in silicon oxide (SiOx) resistive random access memory (RRAM) devices. Our devices had an indium tin oxide/SiOx/p-Si Metal/Oxide/Semiconductor structure, with resistance switching taking place in a 35 nm thick SiOx layer. The optical activity of the devices was investigated by characterising them in a range of voltage and light conditions. Devices respond to illumination at wavelengths in the range of 410-650 nm but are unresponsive at 1152 nm, suggesting that photons are absorbed by the bottom p-type silicon electrode and that generation of free carriers underpins optical activity. Applied light causes charging of devices in the high resistance state (HRS), photocurrent in the low resistance state (LRS), and lowering of the set voltage (required to go from the HRS to LRS) and can be used in conjunction with a voltage bias to trigger switching from the HRS to the LRS. We demonstrate negative correlation between set voltage and applied laser power using a 632.8 nm laser source. We propose that, under illumination, increased electron injection and hence a higher rate of creation of Frenkel pairs in the oxide—precursors for the formation of conductive oxygen vacancy filaments—reduce switching voltages. Our results open up the possibility of light-triggered RRAM devices.

Bimetallic nanoparticles for surface modification and lubrication of MEMS switch contacts

International Nuclear Information System (INIS)

Patton, Steven T; Hu Jianjun; Slocik, Joseph M; Campbell, Angela; Naik, Rajesh R; Voevodin, Andrey A

2008-01-01

Reliability continues to be a critical issue in microelectromechanical systems (MEMS) switches. Failure mechanisms include high contact resistance (R), high adhesion, melting/shorting, and contact erosion. Little previous work has addressed the lubrication of MEMS switches. In this study, bimetallic nanoparticles (NPs) are synthesized using a biotemplated approach and deposited on Au MEMS switch contacts as a nanoparticle-based lubricant. Bimetallic nanoparticles are comprised of a metallic core (∼10 nm diameter gold nanoparticle) with smaller metallic nanoparticles (∼2-3 nm diameter Pd nanoparticles) populating the core surface. Adhesion and resistance (R) were measured during hot switching experiments at low (10 μA) and high (1 mA) current. The Au/Pd NP coated contacts led to reduced adhesion as compared to pure Au contacts with a compromise of slightly higher R. For switches held in the closed position at low current, R gradually decreased over tens of seconds due to increased van der Waals force and growth of the real area of contact with temporal effects being dominant over load effects. Contact behavior transitioned from 'Pd-like' to 'Au-like' during low current cycling experiments. Melting at high current resulted in rapid formation of large real contact area, low and stable R, and minimal effect of load on R. Durability at high current was excellent with no failure through 10 6 hot switching cycles. Improvement at high current is due to controlled nanoscale surface roughness that spreads current through multiple nanocontacts, which restricts the size of melting regions and causes termination of nanowire growth (prevents shorting) during contact opening. Based on these results, bimetallic NPs show excellent potential as surface modifiers/lubricants for MEMS switch contacts

Interference mitigation enhancement of switched-based scheme in over-loaded femtocells

KAUST Repository

Gaaloul, Fakhreddine

2012-06-01

This paper proposes adequate methods to improve the interference mitigation capability of a recently investigated switched-based interference reduction scheme in short-range open-access and over-loaded femtocells. It is assumed that the available orthogonal channels for the femtocell network are distributed among operating access points in close vicinity, where each of which knows its allocated channels a priori. For the case when the feedback links are capacity-limited and the available channels can be universally shared and simultaneously used, the paper presents enhanced schemes to identify a channel to serve the desired scheduled user by maintaining the interference power level within a tolerable range. They attempt to either complement the switched-based scheme by minimum interference channel selection or adopt different interference thresholds on available channels, while aiming to reduce the channels examination load. The performance of the proposed schemes is quantified and then compared with those of the single-threshold switched-based scheme via numerical and simulation results. © 2012 IEEE.

Selective control of multiple ferroelectric switching pathways using a trailing flexoelectric field

Science.gov (United States)

Park, Sung Min; Wang, Bo; Das, Saikat; Chae, Seung Chul; Chung, Jin-Seok; Yoon, Jong-Gul; Chen, Long-Qing; Yang, Sang Mo; Noh, Tae Won

2018-05-01

Flexoelectricity is an electromechanical coupling between electrical polarization and a strain gradient1 that enables mechanical manipulation of polarization without applying an electrical bias2,3. Recently, flexoelectricity was directly demonstrated by mechanically switching the out-of-plane polarization of a uniaxial system with a scanning probe microscope tip3,4. However, the successful application of flexoelectricity in low-symmetry multiaxial ferroelectrics and therefore active manipulation of multiple domains via flexoelectricity have not yet been achieved. Here, we demonstrate that the symmetry-breaking flexoelectricity offers a powerful route for the selective control of multiple domain switching pathways in multiaxial ferroelectric materials. Specifically, we use a trailing flexoelectric field that is created by the motion of a mechanically loaded scanning probe microscope tip. By controlling the SPM scan direction, we can deterministically select either stable 71° ferroelastic switching or 180° ferroelectric switching in a multiferroic magnetoelectric BiFeO3 thin film. Phase-field simulations reveal that the amplified in-plane trailing flexoelectric field is essential for this domain engineering. Moreover, we show that mechanically switched domains have a good retention property. This work opens a new avenue for the deterministic selection of nanoscale ferroelectric domains in low-symmetry materials for non-volatile magnetoelectric devices and multilevel data storage.

Switched capacitor DC-DC converter with switch conductance modulation and Pesudo-fixed frequency control

DEFF Research Database (Denmark)

Larsen, Dennis Øland; Vinter, Martin; Jørgensen, Ivan Harald Holger

A switched capacitor dc-dc converter with frequency-planned control is presented. By splitting the output stage switches in eight segments the output voltage can be regulated with a combination of switching frequency and switch conductance. This allows for switching at predetermined frequencies, 31...

An injection seeded single frequency Nd:YAG Q-switched laser with precisely controllable laser pulse firing time

Science.gov (United States)

Wu, Frank F.; Khizhnyak, Anatoliy; Markov, Vladimir

2010-02-01

We have realized a single frequency Q-switched Nd:YAG laser with precisely controllable lasing time and thus enabled synchronization of multi-laser systems. The use of injection seeding to the slave ring oscillator results in unidirectional Q-switched laser oscillation with suppression of bidirectional Q-switched oscillation that otherwise would be initiated from spontaneous emission if the seeding laser is not present. Under normal condition, the cavity is high in loss during the pumping period; then a Pockels cell opens the cavity to form the pulse build up, with a second Pockels cell to perform cavity dumping, generating the Q-switched pulse output with optimized characteristics. The two Pockels cells can be replaced by a single unit if an adjustable gated electrical pulse is applied to the Pockels cell in which the pulse front is used to open the cavity and the falling edge to dump the laser pulse. Proper selection of the pump parameters and Pockels-cell gating enables operation of the system in a mode in which the Q-switched pulse can be formed only under the seeding condition. The advantage of the realized regime is in stable laser operation with no need in adjustment of the seeded light wavelength and the mode of the cavity. It is found that the frequency of the Q-switched laser radiation matches well to the injected seeded laser mode. By using two-stage amplifiers, an output energy better than 300 mJ has been achieved in MOPA configuration without active control of the cavity length and with pulse width adjustability from several nanoseconds to 20 ns. The Q-switched oscillator operates not only at precisely controlled firing time but also can be tuned over wide range. This will enable multi-laser systems synchronization and frequency locking down each other if necessary.

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.

Digital to analog resistive switching transition induced by graphene buffer layer in strontium titanate based devices.

Science.gov (United States)

Wan, Tao; Qu, Bo; Du, Haiwei; Lin, Xi; Lin, Qianru; Wang, Da-Wei; Cazorla, Claudio; Li, Sean; Liu, Sidong; Chu, Dewei

2018-02-15

Resistive switching behaviour can be classified into digital and analog switching based on its abrupt and gradual resistance change characteristics. Realizing the transition from digital to analog switching in the same device is essential for understanding and controlling the performance of the devices with various switching mechanisms. Here, we investigate the resistive switching in a device made with strontium titanate (SrTiO 3 ) nanoparticles using X-ray diffractometry, scanning electron microscopy, Raman spectroscopy, and direct electrical measurements. It is found that the well-known rupture/formation of Ag filaments is responsible for the digital switching in the device with Ag as the top electrode. To modulate the switching performance, we insert a reduced graphene oxide layer between SrTiO 3 and the bottom FTO electrode owing to its good barrier property for the diffusion of Ag ions and high out-of-plane resistance. In this case, resistive switching is changed from digital to analog as determined by the modulation of interfacial resistance under applied voltage. Based on that controllable resistance, potentiation and depression behaviours are implemented as well. This study opens up new ways for the design of multifunctional devices which are promising for memory and neuromorphic computing applications. Copyright © 2017 Elsevier Inc. All rights reserved.

Instability in time-delayed switched systems induced by fast and random switching

Science.gov (United States)

Guo, Yao; Lin, Wei; Chen, Yuming; Wu, Jianhong

2017-07-01

In this paper, we consider a switched system comprising finitely or infinitely many subsystems described by linear time-delayed differential equations and a rule that orchestrates the system switching randomly among these subsystems, where the switching times are also randomly chosen. We first construct a counterintuitive example where even though all the time-delayed subsystems are exponentially stable, the behaviors of the randomly switched system change from stable dynamics to unstable dynamics with a decrease of the dwell time. Then by using the theories of stochastic processes and delay differential equations, we present a general result on when this fast and random switching induced instability should occur and we extend this to the case of nonlinear time-delayed switched systems as well.

Research Update: Molecular electronics: The single-molecule switch and transistor

Directory of Open Access Journals (Sweden)

Kai Sotthewes

2014-01-01

Full Text Available In order to design and realize single-molecule devices it is essential to have a good understanding of the properties of an individual molecule. For electronic applications, the most important property of a molecule is its conductance. Here we show how a single octanethiol molecule can be connected to macroscopic leads and how the transport properties of the molecule can be measured. Based on this knowledge we have realized two single-molecule devices: a molecular switch and a molecular transistor. The switch can be opened and closed at will by carefully adjusting the separation between the electrical contacts and the voltage drop across the contacts. This single-molecular switch operates in a broad temperature range from cryogenic temperatures all the way up to room temperature. Via mechanical gating, i.e., compressing or stretching of the octanethiol molecule, by varying the contact's interspace, we are able to systematically adjust the conductance of the electrode-octanethiol-electrode junction. This two-terminal single-molecule transistor is very robust, but the amplification factor is rather limited.

Latching micro optical switch

Science.gov (United States)

Garcia, Ernest J; Polosky, Marc A

2013-05-21

An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

Avalanche photoconductive switching

Science.gov (United States)

Pocha, M. D.; Druce, R. L.; Wilson, M. J.; Hofer, W. W.

This paper describes work being done at Lawrence Livermore National Laboratory on the avalanche mode of operation of laser triggered photoconductive switches. We have been able to generate pulses with amplitudes of 2 kV to 35 kV and rise times of 300 to 500 ps, and with a switching gain (energy of output electrical pulse vs energy of trigger optical pulse) of 10(exp 3) to over 10(exp 5). Switches with two very different physical configurations and with two different illumination wavelengths (1.06 micrometer, 890 nm) exhibit very similar behavior. The avalanche switching behavior, therefore, appears to be related to the material parameters rather than the optical wavelength or switch geometry. Considerable further work needs to be done to fully characterize and understand this mode of operation.

Avalanche photoconductive switching

Energy Technology Data Exchange (ETDEWEB)

Pocha, M.D.; Druce, R.L.; Wilson, M.J.; Hofer, W.W.

1989-01-01

This paper describes work being done at Lawrence Livermore National Laboratory on the avalanche mode of operation of laser triggered photoconductive switches. We have been able to generate pulses with amplitudes of 2 kV--35 kV and rise times of 300--500 ps, and with a switching gain (energy of output electrical pulse vs energy of trigger optical pulse) of 10{sup 3} to over 10{sup 5}. Switches with two very different physical configurations and with two different illumination wavelengths (1.06 {mu}m, 890 nm) exhibit very similar behavior. The avalanche switching behavior, therefore, appears to be related to the material parameters rather than the optical wavelength or switch geometry. Considerable further work needs to be done to fully characterize and understand this mode of operation. 3 refs., 6 figs.

160-Gb/s Silicon All-Optical Packet Switch for Buffer-less Optical Burst Switching

DEFF Research Database (Denmark)

Hu, Hao; Ji, Hua; Pu, Minhao

2015-01-01

We experimentally demonstrate a 160-Gb/s Ethernet packet switch using an 8.6-mm-long silicon nanowire for optical burst switching, based on cross phase modulation in silicon. One of the four packets at the bit rate of 160 Gb/s is switched by an optical control signal using a silicon based 1 × 1 all......-optical packet switch. Error free performance (BER silicon packet switch based optical burst switching, which might be desirable for high-speed interconnects within a short...

A progress report of the switch-based data acquisition system prototype project and the application of switches from industry to high-energy physics event building

International Nuclear Information System (INIS)

Barsotti, E.; Booth, A.; Bowden, M.; Swoboda, C.

1990-01-01

A prototype of a data acquisition system based on a new scalable, highly-parallel, open-system architecture is being developed at Fermilab. The major component of the new architecture, the parallel event builder, is based on a telecommunications industry technique used in the implementation of switching systems, a barrel-shift switch. The architecture is scalable both in the expandability of the number of input channels and in the throughput of the system. Because of its scalability, the system is well suited for low to high-rate experiments, test beams and all SSC detectors. The architecture is open in that as new technologies are developed and made into commercial products (e.g., arrays of processors and workstations and standard data links), these new products can be easily integrated into the system with minimal system modifications and no modifications to the system's basic architecture. Scalability and openness should guarantee that the data acquisition system does not become obsolete during the lifetime of the experiment. The paper first gives a description of the architecture and the prototype project and then details both the prototype project's software and hardware status including details of some architecture simulation studies. Suggestions for future R and D work on the new data acquisition system architecture are then described. The paper concludes by examining interconnection networks from industry and their application to event building and to other areas of high-energy physics data acquisition systems

Task Uncertainty Can Account for Mixing and Switch Costs in Task-Switching

Science.gov (United States)

Rennie, Jaime L.

2015-01-01

Cognitive control is required in situations that involve uncertainty or change, such as when resolving conflict, selecting responses and switching tasks. Recently, it has been suggested that cognitive control can be conceptualised as a mechanism which prioritises goal-relevant information to deal with uncertainty. This hypothesis has been supported using a paradigm that requires conflict resolution. In this study, we examine whether cognitive control during task switching is also consistent with this notion. We used information theory to quantify the level of uncertainty in different trial types during a cued task-switching paradigm. We test the hypothesis that differences in uncertainty between task repeat and task switch trials can account for typical behavioural effects in task-switching. Increasing uncertainty was associated with less efficient performance (i.e., slower and less accurate), particularly on switch trials and trials that afford little opportunity for advance preparation. Interestingly, both mixing and switch costs were associated with a common episodic control process. These results support the notion that cognitive control may be conceptualised as an information processor that serves to resolve uncertainty in the environment. PMID:26107646

Controllability of multi-agent systems with periodically switching topologies and switching leaders

Science.gov (United States)

Tian, Lingling; Zhao, Bin; Wang, Long

2018-05-01

This paper considers controllability of multi-agent systems with periodically switching topologies and switching leaders. The concept of m-periodic controllability is proposed, and a criterion for m-periodic controllability is established. The effect of the duration of subsystems on controllability is analysed by utilising a property of analytic functions. In addition, the influence of switching periods on controllability is investigated, and an algorithm is proposed to search for the fewest periods to ensure controllability. A necessary condition for m-periodic controllability is obtained from the perspective of eigenvectors of the subsystems' Laplacian matrices. For a system with switching leaders, it is proved that switching-leader controllability is equivalent to multiple-leader controllability. Furthermore, both the switching order and the tenure of agents being leaders have no effect on the controllability. Some examples are provided to illustrate the theoretical results.

HMSIW-based switchable units using super compact loaded shunt stubs and its applications on SIW/HMSIW switches

Science.gov (United States)

Chen, Haidong; Che, Wenquan; Zhang, Tianyu; Cao, Yue; Feng, Wenjie

2018-06-01

Half-mode substrate integrated waveguide (HMSIW) switchable unit, built by HMSIW section with loaded single or multi-microstrip shunt stub(s), was proposed in this work. Both shorted and opened stubs were studied, investigated and compared, bandwidth enhancement method for proposed switchable units was proposed and demonstrated. Based on these switchable units, narrowband and broadband HMSIW single-pole-single-through (SPST) switches, SIW SPST switch and SIW/HMSIW-based single-pole-double-through (SPDT) switch were designed, fabricated and measured. Good performances were observed experimentally for these proposed circuits, showing the advantages of proposed concept and an excellent candidate for switchable or reconfigurable SIW/HMSIW circuits or systems.

Bimetallic nanoparticles for surface modification and lubrication of MEMS switch contacts

Energy Technology Data Exchange (ETDEWEB)

Patton, Steven T; Hu Jianjun [University of Dayton Research Institute, Dayton, OH 45469-0168 (United States); Slocik, Joseph M; Campbell, Angela; Naik, Rajesh R; Voevodin, Andrey A [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH 45433-7750 (United States)], E-mail: steve.patton@wpafb.af.mil, E-mail: rajesh.naik@wpafb.af.mil

2008-10-08

Reliability continues to be a critical issue in microelectromechanical systems (MEMS) switches. Failure mechanisms include high contact resistance (R), high adhesion, melting/shorting, and contact erosion. Little previous work has addressed the lubrication of MEMS switches. In this study, bimetallic nanoparticles (NPs) are synthesized using a biotemplated approach and deposited on Au MEMS switch contacts as a nanoparticle-based lubricant. Bimetallic nanoparticles are comprised of a metallic core ({approx}10 nm diameter gold nanoparticle) with smaller metallic nanoparticles ({approx}2-3 nm diameter Pd nanoparticles) populating the core surface. Adhesion and resistance (R) were measured during hot switching experiments at low (10 {mu}A) and high (1 mA) current. The Au/Pd NP coated contacts led to reduced adhesion as compared to pure Au contacts with a compromise of slightly higher R. For switches held in the closed position at low current, R gradually decreased over tens of seconds due to increased van der Waals force and growth of the real area of contact with temporal effects being dominant over load effects. Contact behavior transitioned from 'Pd-like' to 'Au-like' during low current cycling experiments. Melting at high current resulted in rapid formation of large real contact area, low and stable R, and minimal effect of load on R. Durability at high current was excellent with no failure through 10{sup 6} hot switching cycles. Improvement at high current is due to controlled nanoscale surface roughness that spreads current through multiple nanocontacts, which restricts the size of melting regions and causes termination of nanowire growth (prevents shorting) during contact opening. Based on these results, bimetallic NPs show excellent potential as surface modifiers/lubricants for MEMS switch contacts.

SESOTHO trial ("Switch Either near Suppression Or THOusand") - switch to second-line versus WHO-guided standard of care for unsuppressed patients on first-line ART with viremia below 1000 copies/mL: protocol of a multicenter, parallel-group, open-label, randomized clinical trial in Lesotho, Southern Africa.

Science.gov (United States)

Amstutz, Alain; Nsakala, Bienvenu Lengo; Vanobberghen, Fiona; Muhairwe, Josephine; Glass, Tracy Renée; Achieng, Beatrice; Sepeka, Mamorena; Tlali, Katleho; Sao, Lebohang; Thin, Kyaw; Klimkait, Thomas; Battegay, Manuel; Labhardt, Niklaus Daniel

2018-02-12

The World Health Organization (WHO) recommends viral load (VL) measurement as the preferred monitoring strategy for HIV-infected individuals on antiretroviral therapy (ART) in resource-limited settings. The new WHO guidelines 2016 continue to define virologic failure as two consecutive VL ≥1000 copies/mL (at least 3 months apart) despite good adherence, triggering switch to second-line therapy. However, the threshold of 1000 copies/mL for defining virologic failure is based on low-quality evidence. Observational studies have shown that individuals with low-level viremia (measurable but below 1000 copies/mL) are at increased risk for accumulation of resistance mutations and subsequent virologic failure. The SESOTHO trial assesses a lower threshold for switch to second-line ART in patients with sustained unsuppressed VL. In this multicenter, parallel-group, open-label, randomized controlled trial conducted in Lesotho, patients on first-line ART with two consecutive unsuppressed VL measurements ≥100 copies/mL, where the second VL is between 100 and 999 copies/mL, will either be switched to second-line ART immediately (intervention group) or not be switched (standard of care, according to WHO guidelines). The primary endpoint is viral resuppression (VL < 50 copies/mL) 9 months after randomization. We will enrol 80 patients, giving us 90% power to detect a difference of 35% in viral resuppression between the groups (assuming two-sided 5% alpha error). For our primary analysis, we will use a modified intention-to-treat set, with those lost to care, death, or crossed over considered failure to resuppress, and using logistic regression models adjusted for the prespecified stratification variables. The SESOTHO trial challenges the current WHO guidelines, assessing an alternative, lower VL threshold for patients with unsuppressed VL on first-line ART. This trial will provide data to inform future WHO guidelines on VL thresholds to recommend switch to second-line ART

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Perspective switching using theories and interpretations

Energy Technology Data Exchange (ETDEWEB)

Farmer, W.M. [Mitre Corp., Bedford, MA (United States)

1996-12-31

An important aspect of intelligence is the ability to switch perspectives. In the course of reasoning about a particular subject matter, it can be convenient to change from one perspective of the subject matter to another perspective, which is often at a different level of abstraction. For example, in some situations it may be advantageous to view a building as a collection of floors and in other situations as a collection of wings. If the arrangement of the rooms is not important for the task at hand, the building might be viewed as simply an unstructured collection of rooms. These are three perspectives on how a building can be decomposed. Utilizing multiple perspectives and freeing moving from one to another is a powerful method for both managing complexity and organizing knowledge. The key idea behind this method is to always employ the {open_quotes}right{close_quotes} perspective for each reasoning task. This talk will address the following two questions: (1) What logical machinery is needed to formalize perspective switching? (2) How can knowledge associated with one perspective be retrieved for use with another perspective?

Optimal switching using coherent control

DEFF Research Database (Denmark)

Kristensen, Philip Trøst; Heuck, Mikkel; Mørk, Jesper

2013-01-01

that the switching time, in general, is not limited by the cavity lifetime. Therefore, the total energy required for switching is a more relevant figure of merit than the switching speed, and for a particular two-pulse switching scheme we use calculus of variations to optimize the switching in terms of input energy....

High frequency switched-mode stimulation can evoke postsynaptic responses in cerebellar principal neurons

Directory of Open Access Journals (Sweden)

Marijn Van Dongen

2015-03-01

Full Text Available This paper investigates the efficacy of high frequency switched-mode neural stimulation. Instead of using a constant stimulation amplitude, the stimulus is switched on and off repeatedly with a high frequency (up to 100kHz duty cycled signal. By means of tissue modeling that includes the dynamic properties of both the tissue material as well as the axon membrane, it is first shown that switched-mode stimulation depolarizes the cell membrane in a similar way as classical constant amplitude stimulation.These findings are subsequently verified using in vitro experiments in which the response of a Purkinje cell is measured due to a stimulation signal in the molecular layer of the cerebellum of a mouse. For this purpose a stimulator circuit is developed that is able to produce a monophasic high frequency switched-mode stimulation signal. The results confirm the modeling by showing that switched-mode stimulation is able to induce similar responses in the Purkinje cell as classical stimulation using a constant current source. This conclusion opens up possibilities for novel stimulation designs that can improve the performance of the stimulator circuitry. Care has to be taken to avoid losses in the system due to the higher operating frequency.

Switch-connected HyperX network

Science.gov (United States)

Chen, Dong; Heidelberger, Philip

2018-02-13

A network system includes a plurality of sub-network planes and global switches. The sub-network planes have a same network topology as each other. Each of the sub-network planes includes edge switches. Each of the edge switches has N ports. Each of the global switches is configured to connect a group of edge switches at a same location in the sub-network planes. In each of the sub-network planes, some of the N ports of each of the edge switches are connected to end nodes, and others of the N ports are connected to other edge switches in the same sub-network plane, other of the N ports are connected to at least one of the global switches.

Statistical Analysis and Modeling of Occupancy Patterns in Open-Plan Offices using Measured Lighting-Switch Data

Energy Technology Data Exchange (ETDEWEB)

Chang, Wen-Kuei; Hong, Tianzhen

2013-01-01

Occupancy profile is one of the driving factors behind discrepancies between the measured and simulated energy consumption of buildings. The frequencies of occupants leaving their offices and the corresponding durations of absences have significant impact on energy use and the operational controls of buildings. This study used statistical methods to analyze the occupancy status, based on measured lighting-switch data in five-minute intervals, for a total of 200 open-plan (cubicle) offices. Five typical occupancy patterns were identified based on the average daily 24-hour profiles of the presence of occupants in their cubicles. These statistical patterns were represented by a one-square curve, a one-valley curve, a two-valley curve, a variable curve, and a flat curve. The key parameters that define the occupancy model are the average occupancy profile together with probability distributions of absence duration, and the number of times an occupant is absent from the cubicle. The statistical results also reveal that the number of absence occurrences decreases as total daily presence hours decrease, and the duration of absence from the cubicle decreases as the frequency of absence increases. The developed occupancy model captures the stochastic nature of occupants moving in and out of cubicles, and can be used to generate a more realistic occupancy schedule. This is crucial for improving the evaluation of the energy saving potential of occupancy based technologies and controls using building simulations. Finally, to demonstrate the use of the occupancy model, weekday occupant schedules were generated and discussed.

FreeSWITCH Cookbook

CERN Document Server

Minessale, Anthony

2012-01-01

This is a problem-solution approach to take your FreeSWITCH skills to the next level, where everything is explained in a practical way. If you are a system administrator, hobbyist, or someone who uses FreeSWITCH on a regular basis, this book is for you. Whether you are a FreeSWITCH expert or just getting started, this book will take your skills to the next level.

Task-set switching under cue-based versus memory-based switching conditions in younger and older adults.

Science.gov (United States)

Kray, Jutta

2006-08-11

Adult age differences in task switching and advance preparation were examined by comparing cue-based and memory-based switching conditions. Task switching was assessed by determining two types of costs that occur at the general (mixing costs) and specific (switching costs) level of switching. Advance preparation was investigated by varying the time interval until the next task (short, middle, very long). Results indicated that the implementation of task sets was different for cue-based switching with random task sequences and memory-based switching with predictable task sequences. Switching costs were strongly reduced under cue-based switching conditions, indicating that task-set cues facilitate the retrieval of the next task. Age differences were found for mixing costs and for switching costs only under cue-based conditions in which older adults showed smaller switching costs than younger adults. It is suggested that older adults adopt a less extreme bias between two tasks than younger adults in situations associated with uncertainty. For cue-based switching with random task sequences, older adults are less engaged in a complete reconfiguration of task sets because of the probability of a further task change. Furthermore, the reduction of switching costs was more pronounced for cue- than memory-based switching for short preparation intervals, whereas the reduction of switch costs was more pronounced for memory- than cue-based switching for longer preparation intervals at least for older adults. Together these findings suggest that the implementation of task sets is functionally different for the two types of task-switching conditions.

Task uncertainty can account for mixing and switch costs in task-switching.

Directory of Open Access Journals (Sweden)

Patrick S Cooper

Full Text Available Cognitive control is required in situations that involve uncertainty or change, such as when resolving conflict, selecting responses and switching tasks. Recently, it has been suggested that cognitive control can be conceptualised as a mechanism which prioritises goal-relevant information to deal with uncertainty. This hypothesis has been supported using a paradigm that requires conflict resolution. In this study, we examine whether cognitive control during task switching is also consistent with this notion. We used information theory to quantify the level of uncertainty in different trial types during a cued task-switching paradigm. We test the hypothesis that differences in uncertainty between task repeat and task switch trials can account for typical behavioural effects in task-switching. Increasing uncertainty was associated with less efficient performance (i.e., slower and less accurate, particularly on switch trials and trials that afford little opportunity for advance preparation. Interestingly, both mixing and switch costs were associated with a common episodic control process. These results support the notion that cognitive control may be conceptualised as an information processor that serves to resolve uncertainty in the environment.

Action of Molecular Switches in GPCRs - Theoretical and Experimental Studies

Science.gov (United States)

Trzaskowski, B; Latek, D; Yuan, S; Ghoshdastider, U; Debinski, A; Filipek, S

2012-01-01

G protein coupled receptors (GPCRs), also called 7TM receptors, form a huge superfamily of membrane proteins that, upon activation by extracellular agonists, pass the signal to the cell interior. Ligands can bind either to extracellular N-terminus and loops (e.g. glutamate receptors) or to the binding site within transmembrane helices (Rhodopsin-like family). They are all activated by agonists although a spontaneous auto-activation of an empty receptor can also be observed. Biochemical and crystallographic methods together with molecular dynamics simulations and other theoretical techniques provided models of the receptor activation based on the action of so-called “molecular switches” buried in the receptor structure. They are changed by agonists but also by inverse agonists evoking an ensemble of activation states leading toward different activation pathways. Switches discovered so far include the ionic lock switch, the 3-7 lock switch, the tyrosine toggle switch linked with the nPxxy motif in TM7, and the transmission switch. The latter one was proposed instead of the tryptophan rotamer toggle switch because no change of the rotamer was observed in structures of activated receptors. The global toggle switch suggested earlier consisting of a vertical rigid motion of TM6, seems also to be implausible based on the recent crystal structures of GPCRs with agonists. Theoretical and experimental methods (crystallography, NMR, specific spectroscopic methods like FRET/BRET but also single-molecule-force-spectroscopy) are currently used to study the effect of ligands on the receptor structure, location of stable structural segments/domains of GPCRs, and to answer the still open question on how ligands are binding: either via ensemble of conformational receptor states or rather via induced fit mechanisms. On the other hand the structural investigations of homo- and heterodimers and higher oligomers revealed the mechanism of allosteric signal transmission and receptor

LCT protective dump-switch tests

International Nuclear Information System (INIS)

Parsons, W.M.

1981-01-01

Each of the six coils in the Large Coil Task (LCT) has a separate power supply, dump resistor, and switching circuit. Each switching circuit contains five switches, two of which are redundant. The three remaining switches perform separate duties in an emergency dump situation. These three switches were tested to determine their ability to meet the LCT conditions

DC switch power supply for vacuum-arc coatings deposition

International Nuclear Information System (INIS)

Zalesskij, D.Yu.; Volkov, Yu.Ya.; Vasil'ev, V.V.; Kozhushko, V.V.; Luchaninov, A.A.; Strel'nitskij, V.E.

2008-01-01

Special DC Switch Power Supply for vacuum-arc deposition was developed and tested in the mode of depositing Al and AlN films. Maximum output power was 6 kW, maximum output current - 120 A, open-circuit voltage - 150 V. The Power Supply allows to adjust and stabilize output current in a wide range. Testing of the Power Supply revealed an advantages over the standard 'Bulat-6' power supply, especially for deposition of non-conductive AlN films.

Switch on, switch off: stiction in nanoelectromechanical switches

KAUST Repository

Wagner, Till J W

2013-06-13

We present a theoretical investigation of stiction in nanoscale electromechanical contact switches. We develop a mathematical model to describe the deflection of a cantilever beam in response to both electrostatic and van der Waals forces. Particular focus is given to the question of whether adhesive van der Waals forces cause the cantilever to remain in the \\'ON\\' state even when the electrostatic forces are removed. In contrast to previous studies, our theory accounts for deflections with large slopes (i.e. geometrically nonlinear). We solve the resulting equations numerically to study how a cantilever beam adheres to a rigid electrode: transitions between \\'free\\', \\'pinned\\' and \\'clamped\\' states are shown to be discontinuous and to exhibit significant hysteresis. Our findings are compared to previous results from linearized models and the implications for nanoelectromechanical cantilever switch design are discussed. © 2013 IOP Publishing Ltd.

Control synthesis of switched systems

CERN Document Server

Zhao, Xudong; Niu, Ben; Wu, Tingting

2017-01-01

This book offers its readers a detailed overview of the synthesis of switched systems, with a focus on switching stabilization and intelligent control. The problems investigated are not only previously unsolved theoretically but also of practical importance in many applications: voltage conversion, naval piloting and navigation and robotics, for example. The book considers general switched-system models and provides more efficient design methods to bring together theory and application more closely than was possible using classical methods. It also discusses several different classes of switched systems. For general switched linear systems and switched nonlinear systems comprising unstable subsystems, it introduces novel ideas such as invariant subspace theory and the time-scheduled Lyapunov function method of designing switching signals to stabilize the underlying systems. For some typical switched nonlinear systems affected by various complex dynamics, the book proposes novel design approaches based on inte...

OpenFlow Deployment and Concept Analysis

Directory of Open Access Journals (Sweden)

Tomas Hegr

2013-01-01

Full Text Available Terms such as SDN and OpenFlow (OF are often used in the research and development of data networks. This paper deals with the analysis of the current state of OpenFlow protocol deployment options as it is the only real representative protocol that enables the implementation of Software Defined Networking outside an academic world. There is introduced an insight into the current state of the OpenFlow specification development at various levels is introduced. The possible limitations associated with this concept in conjunction with the latest version (1.3 of the specification published by ONF are also presented. In the conclusion there presented a demonstrative security application addressing the lack of IPv6 support in real network devices since most of today's switches and controllers support only OF v1.0.

Low-Crosstalk Composite Optical Crosspoint Switches

Science.gov (United States)

Pan, Jing-Jong; Liang, Frank

1993-01-01

Composite optical switch includes two elementary optical switches in tandem, plus optical absorbers. Like elementary optical switches, composite optical switches assembled into switch matrix. Performance enhanced by increasing number of elementary switches. Advantage of concept: crosstalk reduced to acceptably low level at moderate cost of doubling number of elementary switches rather than at greater cost of tightening manufacturing tolerances and exerting more-precise control over operating conditions.

Quantum key based burst confidentiality in optical burst switched networks.

Science.gov (United States)

Balamurugan, A M; Sivasubramanian, A

2014-01-01

The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks.

Quantum Key Based Burst Confidentiality in Optical Burst Switched Networks

Directory of Open Access Journals (Sweden)

A. M. Balamurugan

2014-01-01

Full Text Available The optical burst switching (OBS is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS. This paper deals with employing RC4 (stream cipher to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks.

Organization of the channel-switching process in parallel computer systems based on a matrix optical switch

Science.gov (United States)

Golomidov, Y. V.; Li, S. K.; Popov, S. A.; Smolov, V. B.

1986-01-01

After a classification and analysis of electronic and optoelectronic switching devices, the design principles and structure of a matrix optical switch is described. The switching and pair-exclusion operations in this type of switch are examined, and a method for the optical switching of communication channels is elaborated. Finally, attention is given to the structural organization of a parallel computer system with a matrix optical switch.

Circuit switched optical networks

DEFF Research Database (Denmark)

Kloch, Allan

2003-01-01

Some of the most important components required for enabling optical networking are investigated through both experiments and modelling. These all-optical components are the wavelength converter, the regenerator and the space switch. When these devices become "off-the-shelf" products, optical cross......, it is expected that the optical solution will offer an economical benefit for hight bit rate networks. This thesis begins with a discussion of the expected impact on communications systems from the rapidly growing IP traffic, which is expected to become the dominant source for traffic. IP traffic has some...... characteristics, which are best supported by an optical network. The interest for such an optical network is exemplified by the formation of the ACTS OPEN project which aim was to investigate the feasibility of an optical network covering Europe. Part of the work presented in this thesis is carried out within...

Very high plasma switches. Basic plasma physics and switch technology

International Nuclear Information System (INIS)

Doucet, H.J.; Roche, M.; Buzzi, J.M.

1988-01-01

A review of some high power switches recently developed for very high power technology is made with a special attention to the aspects of plasma physics involved in the mechanisms, which determine the limits of the possible switching parameters

Optical packet switched networks

DEFF Research Database (Denmark)

Hansen, Peter Bukhave

1999-01-01

Optical packet switched networks are investigated with emphasis on the performance of the packet switch blocks. Initially, the network context of the optical packet switched network is described showing that a packet network will provide transparency, flexibility and bridge the granularity gap...... in interferometric wavelength converters is investigated showing that a 10 Gbit/s 19 4x4 swich blocks can be cascaded at a BER of 10-14. An analytical traffic model enables the calculation of the traffice performance of a WDM packet network. Hereby the importance of WDM and wavelegth conversion in the switch blocks...... is established as a flexible means to reduce the optical buffer, e.g., the number of fibre delay lines for a 16x16 switch block is reduced from 23 to 6 by going from 2 to 8 wavelength channels pr. inlet. Additionally, a component count analysis is carried out to illustrate the trade-offs in the switch block...

Full Chain Benchmarking for Open Architecture Airborne ISR Systems: A Case Study for GMTI Radar Applications

Science.gov (United States)

2015-09-15

languages targeting graphics processors [1]. Examples include the CUDA APIs for development on NVIDIA devices, and the more portable OpenCL APIs which...offered by NVIDIA for programming their GPU products. OpenVPX is a switched fabric standard developed specifically for high-performance

Results from a data acquisition system prototype project using a switch-based event builder

Energy Technology Data Exchange (ETDEWEB)

Black, D.; Andresen, J.; Barsotti, E.; Baumbaugh, A.; Esterline, D.; Knickerbocker, K.; Kwarciany, R.; Moore, G.; Patrick, J.; Swoboda, C.; Treptow, K.; Trevizo, O.; Urish, J.; VanConant, R.; Walsh, D. (Fermi National Accelerator Lab., Batavia, IL (United States)); Bowden, M.; Booth, A. (Superconducting Super Collider Lab., Dallas, TX (United States)); Cancelo, G. (La Plata Univ. Nacional (Argentina))

1991-11-01

A prototype of a high bandwidth parallel event builder has been designed and tested. The architecture is based on a simple switching network and is adaptable to a wide variety of data acquisition systems. An eight channel system with a peak throughput of 160 Megabytes per second has been implemented. It is modularly expandable to 64 channels (over one Gigabyte per second). The prototype uses a number of relatively recent commercial technologies, including very high speed fiber-optic data links, high integration crossbar switches and embedded RISC processors. It is based on an open architecture which permits the installation of new technologies with little redesign effort. 5 refs., 6 figs.

Results from a data acquisition system prototype project using a switch-based event builder

International Nuclear Information System (INIS)

Black, D.; Andresen, J.; Barsotti, E.; Baumbaugh, A.; Esterline, D.; Knickerbocker, K.; Kwarciany, R.; Moore, G.; Patrick, J.; Swoboda, C.; Treptow, K.; Trevizo, O.; Urish, J.; VanConant, R.; Walsh, D.; Bowden, M.; Booth, A.; Cancelo, G.

1991-11-01

A prototype of a high bandwidth parallel event builder has been designed and tested. The architecture is based on a simple switching network and is adaptable to a wide variety of data acquisition systems. An eight channel system with a peak throughput of 160 Megabytes per second has been implemented. It is modularly expandable to 64 channels (over one Gigabyte per second). The prototype uses a number of relatively recent commercial technologies, including very high speed fiber-optic data links, high integration crossbar switches and embedded RISC processors. It is based on an open architecture which permits the installation of new technologies with little redesign effort. 5 refs., 6 figs

Open-Source Java for Teaching Computational Physics

Science.gov (United States)

Wolfgang, Christian; Gould, Harvey; Gould, Joshua; Tobochnik, Jan

2001-11-01

The switch from procedural to object-oriented (OO) programming has produced dramatic changes in professional software design. OO techniques have not, however, been widely adopted in computational physics. Although most physicists are familiar with procedural languages such as Fortran, few physicists have formal training in computer science and few therefore have made the switch to OO programming. The continued use of procedural languages in education is due, in part, to the lack of up-to-date curricular materials that combine current computational physics research topics with an OO framework. This talk describes an Open-Source curriculum development project to produce such material. Examples will be presented that show how OO techniques can be used to encapsulate the relevant Physics, the analysis, and the associated numerical methods.

Optical switching systems using nanostructures

DEFF Research Database (Denmark)

Stubkjær, Kristian

2004-01-01

High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems.......High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems....

Practical switching power supply design

CERN Document Server

Brown, Martin C

1990-01-01

Take the ""black magic"" out of switching power supplies with Practical Switching Power Supply Design! This is a comprehensive ""hands-on"" guide to the theory behind, and design of, PWM and resonant switching supplies. You'll find information on switching supply operation and selecting an appropriate topology for your application. There's extensive coverage of buck, boost, flyback, push-pull, half bridge, and full bridge regulator circuits. Special attention is given to semiconductors used in switching supplies. RFI/EMI reduction, grounding, testing, and safety standards are also deta

Switching Phenomena

Science.gov (United States)

Stanley, H. E.; Buldyrev, S. V.; Franzese, G.; Havlin, S.; Mallamace, F.; Mazza, M. G.; Kumar, P.; Plerou, V.; Preis, T.; Stokely, K.; Xu, L.

One challenge of biology, medicine, and economics is that the systems treated by these serious scientific disciplines can suddenly "switch" from one behavior to another, even though they possess no perfect metronome in time. As if by magic, out of nothing but randomness one finds remarkably fine-tuned processes in time. The past century has, philosophically, been concerned with placing aside the human tendency to see the universe as a fine-tuned machine. Here we will address the challenge of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at some of the many temporal patterns in physics, economics, and medicine and even begin to characterize the switching phenomena that enable a system to pass from one state to another. We discuss some applications of correlated randomness to understanding switching phenomena in various fields. Specifically, we present evidence from experiments and from computer simulations supporting the hypothesis that water's anomalies are related to a switching point (which is not unlike the "tipping point" immortalized by Malcolm Gladwell), and that the bubbles in economic phenomena that occur on all scales are not "outliers" (another Gladwell immortalization).

Complementary resistive switching in BaTiO3/NiO bilayer with opposite switching polarities

Science.gov (United States)

Li, Shuo; Wei, Xianhua; Lei, Yao; Yuan, Xincai; Zeng, Huizhong

2016-12-01

Resistive switching behaviors have been investigated in the Au/BaTiO3/NiO/Pt structure by stacking the two elements with different switching types. The conducting atomic force microscope measurements on BaTiO3 thin films and NiO thin films suggest that with the same active resistive switching region, the switching polarities in the two semiconductors are opposite to each other. It is in agreement with the bipolar hysteresis I-V curves with opposite switching polarities for single-layer devices. The bilayer devices show complementary resistive switching (CRS) without electroforming and unipolar resistive switching (URS) after electroforming. The coexistence of CRS and URS is mainly ascribed to the co-effect of electric field and Joule heating mechanisms, indicating that changeable of resistance in this device is dominated by the redistribution of oxygen vacancies in BaTiO3 and the formation, disruption, restoration of conducting filaments in NiO. CRS in bilayer with opposite switching polarities is effective to solve the sneak current without the introduction of any selector elements or an additional metal electrode.

Optimization of multi-branch switched diversity systems

KAUST Repository

Nam, Haewoon

2009-10-01

A performance optimization based on the optimal switching threshold(s) for a multi-branch switched diversity system is discussed in this paper. For the conventional multi-branch switched diversity system with a single switching threshold, the optimal switching threshold is a function of both the average channel SNR and the number of diversity branches, where computing the optimal switching threshold is not a simple task when the number of diversity branches is high. The newly proposed multi-branch switched diversity system is based on a sequence of switching thresholds, instead of a single switching threshold, where a different diversity branch uses a different switching threshold for signal comparison. Thanks to the fact that each switching threshold in the sequence can be optimized only based on the number of the remaining diversity branches, the proposed system makes it easy to find these switching thresholds. Furthermore, some selected numerical and simulation results show that the proposed switched diversity system with the sequence of optimal switching thresholds outperforms the conventional system with the single optimal switching threshold. © 2009 IEEE.

Hybrid switch for resonant power converters

Science.gov (United States)

Lai, Jih-Sheng; Yu, Wensong

2014-09-09

A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

Switched-based interference reduction scheme for open-access overlaid cellular networks

KAUST Repository

Radaydeh, Redha Mahmoud Mesleh; Alouini, Mohamed-Slim

2012-01-01

coordination between access points is infeasible. This paper targets interference management in such overlaid networks. It is assumed that the femtocells employ the open-access strategy to reduce cross-tier interference, and can share resources concurrently

Open- and Closed-Skill Exercise Interventions Produce Different Neurocognitive Effects on Executive Functions in the Elderly: A 6-Month Randomized, Controlled Trial

Directory of Open Access Journals (Sweden)

Chia-Liang Tsai

2017-09-01

Full Text Available This study aimed to explore the effects of open- and closed-skill exercise interventions on the neurocognitive performance of executive functions in the elderly. Sixty-four healthy elderly males were randomly assigned to either a closed-skill (bike riding or brisk walking/jogging, n = 22, open-skill (table tennis, n = 21, or control (n = 21 group. Various neuropsychological [e.g., accuracy rates (AR and reaction time (RT] and electrophysiological [e.g., event-related potential (ERP P3 component] measures were assessed during a variant of the task-switching paradigm, as well as an N-back task at baseline and after either a 6-month exercise intervention or control period. The results showed that, when performing the task-switching paradigm, the two exercise groups relative to control group showed significantly faster RTs in the switch trials after the exercise intervention. However, the RT facilitation in the non-switch and switch trials post-exercise relative to pre-exercise only emerged in the open-skill group. In terms of the N-back task, the two exercise groups significantly increased ARs in the 1-back condition after the exercise intervention, and the beneficial AR effect on the 2-back condition only emerged in the closed-skill group. In addition, the two exercise groups exhibited significantly larger P3 amplitudes on the frontal-to-parietal cortex areas after the exercise intervention relative to the baseline when performing the two cognitive tasks. These neurocognitive results still remained unchanged even when the confounding factors (e.g., cardiorespiratory fitness, social participation, and BMI were controlled for. The present study concluded that, although 6-month open- and closed-skill exercise interventions facilitate overall electrophysiological effects (i.e., increased ERP P3 amplitudes on the frontal-to-parietal cortices in the elderly, the two exercise modes produced different levels of neuropsychologically beneficial effects on

Tutorial: Integrated-photonic switching structures

Science.gov (United States)

Soref, Richard

2018-02-01

Recent developments in waveguided 2 × 2 and N × M photonic switches are reviewed, including both broadband and narrowband resonant devices for the Si, InP, and AlN platforms. Practical actuation of switches by electro-optical and thermo-optical techniques is discussed. Present datacom-and-computing applications are reviewed, and potential applications are proposed for chip-scale photonic and optoelectronic integrated switching networks. Potential is found in the reconfigurable, programmable "mesh" switches that enable a promising group of applications in new areas beyond those in data centers and cloud servers. Many important matrix switches use gated semiconductor optical amplifiers. The family of broadband, directional-coupler 2 × 2 switches featuring two or three side-coupled waveguides deserves future experimentation, including devices that employ phase-change materials. The newer 2 × 2 resonant switches include standing-wave resonators, different from the micro-ring traveling-wave resonators. The resonant devices comprise nanobeam interferometers, complex-Bragg interferometers, and asymmetric contra-directional couplers. Although the fast, resonant devices offer ultralow switching energy, ˜1 fJ/bit, they have limitations. They require several trade-offs when deployed, but they do have practical application.

Model-based open-loop control design for a hydraulic brake system with switching solenoid valves; Modellbasierter Steuerungsentwurf fuer ein hydraulisches Bremssystem mit magnetischen Schaltventilen

Energy Technology Data Exchange (ETDEWEB)

Lolenko, K.; Fehn, A.A.R. [Robert Bosch GmbH, Abstatt (Germany). CC/ESM

2007-02-15

This paper presents a novel concept for the model-based open-loop control design of switching solenoid valves. The control is suitable for the wheel brake calliper pressure setting during vehicle dynamics control, as e. g. by ESP or ABS [1;11]. For the control design the reduced model, taking into account all essential nonlinearities of the system as well as environmental effects (e.g. temperature), was derived from the detailed simulation model. The transition times and other characteristic time intervals describing the dynamic behaviour of the solenoid valve are calculated from the equations of the reduced model through symbolic integration or approximative by means of taylor series. The calculated time intervals serve to define the control impulse duration of the valve from the desired calliper pressure. In simulation studies the designed control has been proven to be an efficient approach and allows improved pressure control accuracy for conventional brake systems. (orig.)

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

DEFF Research Database (Denmark)

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

2013-01-01

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

Nanocrystalline Si pathway induced unipolar resistive switching behavior from annealed Si-rich SiNx/SiNy multilayers

International Nuclear Information System (INIS)

Jiang, Xiaofan; Ma, Zhongyuan; Yang, Huafeng; Yu, Jie; Wang, Wen; Zhang, Wenping; Li, Wei; Xu, Jun; Xu, Ling; Chen, Kunji; Huang, Xinfan; Feng, Duan

2014-01-01

Adding a resistive switching functionality to a silicon microelectronic chip is a new challenge in materials research. Here, we demonstrate that unipolar and electrode-independent resistive switching effects can be realized in the annealed Si-rich SiN x /SiN y multilayers with high on/off ratio of 10 9 . High resolution transmission electron microscopy reveals that for the high resistance state broken pathways composed of discrete nanocrystalline silicon (nc-Si) exist in the Si nitride multilayers. While for the low resistance state the discrete nc-Si regions is connected, forming continuous nc-Si pathways. Based on the analysis of the temperature dependent I-V characteristics and HRTEM photos, we found that the break-and-bridge evolution of nc-Si pathway is the origin of resistive switching memory behavior. Our findings provide insights into the mechanism of the resistive switching behavior in nc-Si films, opening a way for it to be utilized as a material in Si-based memories.

Nanocrystalline Si pathway induced unipolar resistive switching behavior from annealed Si-rich SiNx/SiNy multilayers

Science.gov (United States)

Jiang, Xiaofan; Ma, Zhongyuan; Yang, Huafeng; Yu, Jie; Wang, Wen; Zhang, Wenping; Li, Wei; Xu, Jun; Xu, Ling; Chen, Kunji; Huang, Xinfan; Feng, Duan

2014-09-01

Adding a resistive switching functionality to a silicon microelectronic chip is a new challenge in materials research. Here, we demonstrate that unipolar and electrode-independent resistive switching effects can be realized in the annealed Si-rich SiNx/SiNy multilayers with high on/off ratio of 109. High resolution transmission electron microscopy reveals that for the high resistance state broken pathways composed of discrete nanocrystalline silicon (nc-Si) exist in the Si nitride multilayers. While for the low resistance state the discrete nc-Si regions is connected, forming continuous nc-Si pathways. Based on the analysis of the temperature dependent I-V characteristics and HRTEM photos, we found that the break-and-bridge evolution of nc-Si pathway is the origin of resistive switching memory behavior. Our findings provide insights into the mechanism of the resistive switching behavior in nc-Si films, opening a way for it to be utilized as a material in Si-based memories.

Complementary resistive switching in BaTiO{sub 3}/NiO bilayer with opposite switching polarities

Energy Technology Data Exchange (ETDEWEB)

Li, Shuo [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Institut d’Electronique de Micro-électronique et de Nanotechnologie (IEMN), CNRS, Université des Sciences et Technologies de Lille, avenue Poincaré, BP 60069, 59652, Villeneuve d’Ascq cedex (France); Wei, Xianhua, E-mail: weixianhua@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Lei, Yao [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronics Science and Technology of China, Chengdu 610054 (China); Yuan, Xincai [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Zeng, Huizhong [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronics Science and Technology of China, Chengdu 610054 (China)

2016-12-15

Graphical abstract: Au/BaTiO{sub 3}/NiO/Pt bilayer device shows complementary resistive switching (CRS) without electroforming which is mainly ascribed to anti-serial stack of two RRAM cells with bipolar behaviors. - Highlights: • Complementary resistive switching (CRS) has been investigated in Au/BaTiO{sub 3}/NiO/Pt by stacking the two elements with different switching types. • The realization of complementary resistive switching (CRS) is mainly ascribed to the anti-serial stack of two RRAM cells with bipolar behaviors. • Complementary resistive switching (CRS) in bilayer is effective to solve the sneak current problem briefly and economically. - Abstract: Resistive switching behaviors have been investigated in the Au/BaTiO{sub 3}/NiO/Pt structure by stacking the two elements with different switching types. The conducting atomic force microscope measurements on BaTiO{sub 3} thin films and NiO thin films suggest that with the same active resistive switching region, the switching polarities in the two semiconductors are opposite to each other. It is in agreement with the bipolar hysteresis I–V curves with opposite switching polarities for single-layer devices. The bilayer devices show complementary resistive switching (CRS) without electroforming and unipolar resistive switching (URS) after electroforming. The coexistence of CRS and URS is mainly ascribed to the co-effect of electric field and Joule heating mechanisms, indicating that changeable of resistance in this device is dominated by the redistribution of oxygen vacancies in BaTiO{sub 3} and the formation, disruption, restoration of conducting filaments in NiO. CRS in bilayer with opposite switching polarities is effective to solve the sneak current without the introduction of any selector elements or an additional metal electrode.

Switch on the competition. Causes, consequences and policy implications of consumer switching costs

International Nuclear Information System (INIS)

Pomp, M.; Shestalova, V.; Rangel, L.

2005-09-01

The success or failure of reforms aimed at liberalising markets depends to an important degree on consumer behaviour. If consumers do not base their choices on differences in prices and quality, competition between firms may be weak and the benefits of liberalisation to consumers may be small. One possible reason why consumers may respond only weakly to differences in price and quality is high costs of switching to another firm. This report presents a framework for analysing markets with switching costs and applies the framework in two empirical case studies. The first case study analyses the residential energy market, the second focuses on the market for social health insurance. In both markets, there are indications that switching costs are substantial. The report discusses policy options for reducing switching costs and for alleviating the consequences of switching costs

Switch on the competition. Causes, consequences and policy implications of consumer switching costs

Energy Technology Data Exchange (ETDEWEB)

Pomp, M.; Shestalova, V.; Rangel, L.

2005-09-15

The success or failure of reforms aimed at liberalising markets depends to an important degree on consumer behaviour. If consumers do not base their choices on differences in prices and quality, competition between firms may be weak and the benefits of liberalisation to consumers may be small. One possible reason why consumers may respond only weakly to differences in price and quality is high costs of switching to another firm. This report presents a framework for analysing markets with switching costs and applies the framework in two empirical case studies. The first case study analyses the residential energy market, the second focuses on the market for social health insurance. In both markets, there are indications that switching costs are substantial. The report discusses policy options for reducing switching costs and for alleviating the consequences of switching costs.

Military spending and economic growth in China: a regime-switching analysis

OpenAIRE

Menla Ali, F; Dimitraki, O

2014-01-01

This article has been made available through the Brunel Open Access Publishing Fund. This article investigates the impact of military spending changes on economic growth in China over the period 1953 to 2010. Using two-state Markov-switching specifications, the results suggest that the relationship between military spending changes and economic growth is state dependent. Specifically, the results show that military spending changes affect the economic growth negatively during a slower grow...

Optically triggered high voltage switch network and method for switching a high voltage

Science.gov (United States)

El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

1993-01-19

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

Optically triggered high voltage switch network and method for switching a high voltage

Energy Technology Data Exchange (ETDEWEB)

El-Sharkawi, Mohamed A. (Renton, WA); Andexler, George (Everett, WA); Silberkleit, Lee I. (Mountlake Terrace, WA)

1993-01-19

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

Software Defined Networking (SDN) controlled all optical switching networks with multi-dimensional switching architecture

Science.gov (United States)

Zhao, Yongli; Ji, Yuefeng; Zhang, Jie; Li, Hui; Xiong, Qianjin; Qiu, Shaofeng

2014-08-01

Ultrahigh throughout capacity requirement is challenging the current optical switching nodes with the fast development of data center networks. Pbit/s level all optical switching networks need to be deployed soon, which will cause the high complexity of node architecture. How to control the future network and node equipment together will become a new problem. An enhanced Software Defined Networking (eSDN) control architecture is proposed in the paper, which consists of Provider NOX (P-NOX) and Node NOX (N-NOX). With the cooperation of P-NOX and N-NOX, the flexible control of the entire network can be achieved. All optical switching network testbed has been experimentally demonstrated with efficient control of enhanced Software Defined Networking (eSDN). Pbit/s level all optical switching nodes in the testbed are implemented based on multi-dimensional switching architecture, i.e. multi-level and multi-planar. Due to the space and cost limitation, each optical switching node is only equipped with four input line boxes and four output line boxes respectively. Experimental results are given to verify the performance of our proposed control and switching architecture.

Electromechanical magnetization switching

Energy Technology Data Exchange (ETDEWEB)

Chudnovsky, Eugene M. [Department of Physics and Astronomy, Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Jaafar, Reem [Department of Mathematics, Engineering and Computer Science, LaGuardia Community College, The City University of New York, 31-10 Thomson Avenue, Long Island City, New York 11101 (United States)

2015-03-14

We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

Electromechanical magnetization switching

International Nuclear Information System (INIS)

Chudnovsky, Eugene M.; Jaafar, Reem

2015-01-01

We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained

JUNOS Enterprise Switching

CERN Document Server

Reynolds, Harry

2009-01-01

JUNOS Enterprise Switching is the only detailed technical book on Juniper Networks' new Ethernet-switching EX product platform. With this book, you'll learn all about the hardware and ASIC design prowess of the EX platform, as well as the JUNOS Software that powers it. Not only is this extremely practical book a useful, hands-on manual to the EX platform, it also makes an excellent study guide for certification exams in the JNTCP enterprise tracks. The authors have based JUNOS Enterprise Switching on their own Juniper training practices and programs, as well as the configuration, maintenanc

Scalable In-Band Optical Notch-Filter Labeling for Ultrahigh Bit Rate Optical Packet Switching

DEFF Research Database (Denmark)

Medhin, Ashenafi Kiros; Galili, Michael; Oxenløwe, Leif Katsuo

2014-01-01

We propose a scalable in-band optical notch-filter labeling scheme for optical packet switching of high-bit-rate data packets. A detailed characterization of the notch-filter labeling scheme and its effect on the quality of the data packet is carried out in simulation and verified by experimental...... demonstrations. The scheme is able to generate more than 91 different labels that can be applied to 640-Gb/s optical time division multiplexed packets causing an eye opening penalty of $1.2-dB. Experimental demonstration shows that up to 256 packets can be uniquely labeled by employing up to eight notch filters...... with only 0.9-dB power penalty to achieve BER of 1E-9. Using the proposed labeling scheme, optical packet switching of 640 Gb/s data packets is experimentally demonstrated in which two data packets are labeled by making none and one spectral hole using a notch filter and are switched using a LiNbO$_3...

Comparison of switching control algorithms effective in restricting the switching in the neighborhood of the origin

International Nuclear Information System (INIS)

Joung, JinWook; Chung, Lan; Smyth, Andrew W

2010-01-01

The active interaction control (AIC) system consisting of a primary structure, an auxiliary structure and an interaction element was proposed to protect the primary structure against earthquakes and winds. The objective of the AIC system in reducing the responses of the primary structure is fulfilled by activating or deactivating the switching between the engagement and the disengagement of the primary and auxiliary structures through the interaction element. The status of the interaction element is controlled by switching control algorithms. The previously developed switching control algorithms require an excessive amount of switching, which is inefficient. In this paper, the excessive amount of switching is restricted by imposing an appropriately designed switching boundary region, where switching is prohibited, on pre-designed engagement–disengagement conditions. Two different approaches are used in designing the newly proposed AID-off and AID-off 2 algorithms. The AID-off 2 algorithm is designed to affect deactivated switching regions explicitly, unlike the AID-off algorithm, which follows the same procedure of designing the engagement–disengagement conditions of the previously developed algorithms, by using the current status of the AIC system. Both algorithms are shown to be effective in reducing the amount of switching times triggered from the previously developed AID algorithm under an appropriately selected control sampling period for different earthquakes, but the AID-off 2 algorithm outperforms the AID-off algorithm in reducing the number of switching times

Elements of magnetic switching

International Nuclear Information System (INIS)

Aaland, K.

1983-01-01

This chapter describes magnetic switching as a method of connecting a capacitor bank (source) to a load; reviews several successful applications of magnetic switching, and discusses switching transformers, limitations and future possibilities. Some of the inflexibility and especially the high cost of magnetic materials may be overcome with the availability of the new splash cooled ribbons (Metglas). Experience has shown that magnetics works despite shock, radiation or noise interferences

Know-How on design of switching regulator

International Nuclear Information System (INIS)

1985-08-01

This book introduces switching regulator from base to application, which deals with fundamentals of switching regulator such as the reason of boom about switching regulator, understanding simple circuit without electric transformer and decision of circuit type with input voltage and output voltage, configuration and characteristic of switching regulator, a concrete design of switching regulator, pulse width control circuit and protection circuit, concrete circuit examples of switching power and the point of switching regulator.

Voltage-induced switching of an antiferromagnetically ordered topological Dirac semimetal

Science.gov (United States)

Kim, Youngseok; Kang, Kisung; Schleife, André; Gilbert, Matthew J.

2018-04-01

An antiferromagnetic semimetal has been recently identified as a new member of topological semimetals that may host three-dimensional symmetry-protected Dirac fermions. A reorientation of the Néel vector may break the underlying symmetry and open a gap in the quasiparticle spectrum, inducing the (semi)metal-insulator transition. Here, we predict that such a transition may be controlled by manipulating the chemical potential location of the material. We perform both analytical and numerical analysis on the thermodynamic potential of the model Hamiltonian and find that the gapped spectrum is preferred when the chemical potential is located at the Dirac point. As the chemical potential deviates from the Dirac point, the system shows a possible transition from the gapped to the gapless phase and switches the corresponding Néel vector configuration. We perform density functional theory calculations to verify our analysis using a realistic material and discuss a two terminal transport measurement as a possible route to identify the voltage-induced switching of the Néel vector.

MENGAPA PERUSAHAAN MELAKUKAN AUDITOR SWITCH?

Directory of Open Access Journals (Sweden)

Kadek Sumadi

2011-01-01

Full Text Available The existence of a large number of accounting firms allowsprovides companies choices whether to stay with current firm or switchto another accounting firm. Decision of Minister of FinanceNo.423/KMK.06/2002 states that a company must switch auditor afterfive years of consecutive assignment. This is mandatory. The questionrises when a company voluntarily switches its auditor. Why does thishappen?One of the reasons is that management does not satisfy withauditor opinion, except for unqualified opinion. New management teamwould directly or indirectly encourage auditor switch to align accountingand reporting policies. Moreover an expanding company expects positivereaction when it does auditor switch. Profitability is also one reason fora company to switch auditor, for example, when a company earns moreprofit it tends to hire more credible auditor. On the other hand, when thecompany faces a financial distress, it probably would switch auditor aswell.

Principles of broadband switching and networking

CERN Document Server

Liew, Soung C

2010-01-01

An authoritative introduction to the roles of switching and transmission in broadband integrated services networks Principles of Broadband Switching and Networking explains the design and analysis of switch architectures suitable for broadband integrated services networks, emphasizing packet-switched interconnection networks with distributed routing algorithms. The text examines the mathematical properties of these networks, rather than specific implementation technologies. Although the pedagogical explanations in this book are in the context of switches, many of the fundamenta

Error rate degradation due to switch crosstalk in large modular switched optical networks

DEFF Research Database (Denmark)

Saxtoft, Christian; Chidgey, P.

1993-01-01

A theoretical model of an optical network incorporating wavelength selective elements, amplifiers, couplers and switches is presented. The model is used to evaluate a large modular switch optical network that provides the capability of adapting easily to changes in network traffic requirements. T....... The network dimensions are shown to be limited by the optical crosstalk in the switch matrices and by the polarization dependent loss in the optical components...

Pemodelan Markov Switching Autoregressive

OpenAIRE

Ariyani, Fiqria Devi; Warsito, Budi; Yasin, Hasbi

2014-01-01

Transition from depreciation to appreciation of exchange rate is one of regime switching that ignored by classic time series model, such as ARIMA, ARCH, or GARCH. Therefore, economic variables are modeled by Markov Switching Autoregressive (MSAR) which consider the regime switching. MLE is not applicable to parameters estimation because regime is an unobservable variable. So that filtering and smoothing process are applied to see the regime probabilities of observation. Using this model, tran...

Energy losses in switches

International Nuclear Information System (INIS)

Martin, T.H.; Seamen, J.F.; Jobe, D.O.

1993-01-01

The authors experiments show energy losses between 2 and 10 times that of the resistive time predictions. The experiments used hydrogen, helium, air, nitrogen, SF 6 polyethylene, and water for the switching dielectric. Previously underestimated switch losses have caused over predicting the accelerator outputs. Accurate estimation of these losses is now necessary for new high-efficiency pulsed power devices where the switching losses constitute the major portion of the total energy loss. They found that the switch energy losses scale as (V peak I peak ) 1.1846 . When using this scaling, the energy losses in any of the tested dielectrics are almost the same. This relationship is valid for several orders of magnitude and suggested a theoretical basis for these results. Currents up to .65 MA, with voltages to 3 MV were applied to various gaps during these experiments. The authors data and the developed theory indicates that the switch power loss continues for a much longer time than the resistive time, with peak power loss generally occurring at peak current in a ranging discharge instead of the early current time. All of the experiments were circuit code modeled after developing a new switch loss version based on the theory. The circuit code predicts switch energy loss and peak currents as a function of time. During analysis of the data they noticed slight constant offsets between the theory and data that depended on the dielectric. They modified the plasma conductivity for each tested dielectric to lessen this offset

Low-Voltage Switched-Capacitor Circuits

DEFF Research Database (Denmark)

Bidari, E.; Keskin, M.; Maloberti, F.

1999-01-01

Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications.......Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications....

Bootstrapped Low-Voltage Analog Switches

DEFF Research Database (Denmark)

Steensgaard-Madsen, Jesper

1999-01-01

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

Timer switch to convert suction apparatus for negative pressure wound therapy application

Directory of Open Access Journals (Sweden)

Surath Amarnath

2014-01-01

Full Text Available Background: Negative pressure wound therapy (NPWT is an established modality in the treatment of chronic wounds, open fractures, and post-operative wound problems. This method has not been widely used due to the high cost of equipment and consumables. This study demonstrates an indigenously developed apparatus which gives comparable results at a fraction of the cost. Readily available materials are used for the air-tight dressing. Materials and Methods: Equipment consists of suction apparatus with adjustable pressure valve set to a pressure 125-150 mmHg. An electronic timer switch with a sequential working time of 5 min and a standby time of 3 min provides the required intermittent negative pressure. Readily available materials such as polyvinyl alcohol sponge, suction drains and steridrapes were used to provide an air tight wound cover. Results: A total of 90 cases underwent 262 NPWT applications from 2009 to 2014. This series, comprised of 30 open fractures, 21 post-operative and 39 chronic wounds. The wound healing rate in our study was comparable to other published studies using NPWT. Conclusion: The addition of electronic timer switch will convert a suction apparatus into NPWT machine, and the results are equally effective compared to more expensive counter parts. The use of indigenous dressing materials reduces the cost significantly.

Characteristics of magnetic switch used as main switch of solid-state accelerator

International Nuclear Information System (INIS)

Li Song; Qian Baoliang; Yang Hanwu; Meng Zhipeng; Yang Shi

2012-01-01

In order to improve the performance of solid-state accelerator, the characteristics of magnetic switch used as the main switch of the accelerator have been investigated. The volume of magnetic core, the loss, and saturated inductance of the magnetic switch have been derived. The results show that the spacing factor of the magnetic switch reaches the peak when the height of the magnetic materials is 0.05 m for selected magnetic cores. The saturated inductance of the windings changes slowly when the average magnetic path length of the core is greater than 1 m. The physical process of saturation in the cores was analyzed by using saturation-wave theory. The rise-time factor of the output pulse was derived. The thickness, resistivity and magnetic path length difference of the magnetic core are shown to be key parameters affecting the rise-time factor. (authors)

A new Zero-Voltage-Transition PWM switching cell

Energy Technology Data Exchange (ETDEWEB)

Grigore, V. [Electronics and Telecommunications Faculty `Politebuica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

1997-12-31

In this paper a new Zero-Voltage-Transition (ZVT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus an auxiliary circuit (consisting of one active switch and some reactive components). The auxiliary circuit is inactive during the ON and OFF intervals of the switches in the normal PWM switch. However, the transitions between the two states are controlled by the auxiliary circuit. Prior to turn-on, the voltage across the active switch in the PWM cell is forced to zero, thus the turn-on losses of the active switch are practically eliminated. At turn-off the auxiliary circuit behaves like a non-dissipative passive snubber reducing the turn-off losses to a great extent. Zero-Voltage-Transition switching technique almost eliminates switching losses. The active switch operates under ZVT conditions, the passive switch (diode) has a controlled reverse recovery, and the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 6 refs.

Recent developments in switching theory

CERN Document Server

Mukhopadhyay, Amar

2013-01-01

Electrical Science Series: Recent Developments in Switching Theory covers the progress in the study of the switching theory. The book discusses the simplified proof of Post's theorem on completeness of logic primitives; the role of feedback in combinational switching circuits; and the systematic procedure for the design of Lupanov decoding networks. The text also describes the classical results on counting theorems and their application to the classification of switching functions under different notions of equivalence, including linear and affine equivalences. The development of abstract har

Amorphous metal based nanoelectromechanical switch

KAUST Repository

Mayet, Abdulilah M.; Smith, Casey; Hussain, Muhammad Mustafa

2013-01-01

Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

Switched-capacitor isolated LED driver

Science.gov (United States)

Sanders, Seth R.; Kline, Mitchell

2016-03-22

A switched-capacitor voltage converter which is particularly well-suited for receiving a line voltage from which to drive current through a series of light emitting diodes (LEDs). Input voltage is rectified in a multi-level rectifier network having switched capacitors in an ascending-bank configuration for passing voltages in uniform steps between zero volts up to full received voltage V.sub.DC. A regulator section, operating on V.sub.DC, comprises switched-capacitor stages of H-bridge switching and flying capacitors. A current controlled oscillator drives the states of the switched-capacitor stages and changes its frequency to maintain a constant current to the load. Embodiments are described for isolating the load from the mains, utilizing an LC tank circuit or a multi-primary-winding transformer.

Amorphous metal based nanoelectromechanical switch

KAUST Repository

Mayet, Abdulilah M.

2013-04-01

Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

A new Zero-Current-Transition PWM switching cell

Energy Technology Data Exchange (ETDEWEB)

Grigore, V. [Electronics and Telecommunications Faculty, `Politechnica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

1997-12-31

In this paper a new Zero-Current-Transition (ZCT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus as auxiliary circuit. The auxiliary circuit is inactive during the ON ad OFF intervals of the switches in the normal PWM switch. The transitions between the two states are controlled by the auxiliary circuit. Prior to turn-off, the current through the active switch in the PWM cell is forced to zero, thus the turn-off losses of the active switch are practically eliminated. At turn-on the auxiliary circuit slows down the growing rate of the current through the main switch. Thus, turn-on losses are also very much reduced. The active switch operates under ZCT conditions, the passive switch (diode) has a controlled reverse recovery, while the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 3 refs.

Call for Papers: Photonics in Switching

Science.gov (United States)

Wosinska, Lena; Glick, Madeleine

2006-04-01

Call for Papers: Photonics in Switching Guest Editors: Lena Wosinska, Royal Institute of Technology (KTH) / ICT Sweden Madeleine Glick, Intel Research, Cambridge, UK Technologies based on DWDM systems allow data transmission with bit rates of Tbit/s on a single fiber. To facilitate this enormous transmission volume, high-capacity and high-speed network nodes become inevitable in the optical network. Wideband switching, WDM switching, optical burst switching (OBS), and optical packet switching (OPS) are promising technologies for harnessing the bandwidth of WDM optical fiber networks in a highly flexible and efficient manner. As a number of key optical component technologies approach maturity, photonics in switching is becoming an increasingly attractive and practical solution for the next-generation of optical networks. The scope of this special issue is focused on the technology and architecture of optical switching nodes, including the architectural and algorithmic aspects of high-speed optical networks. Scope of Submission The scope of the papers includes, but is not limited to, the following topics: WDM node architectures Novel device technologies enabling photonics in switching, such as optical switch fabrics, optical memory, and wavelength conversion Routing protocols WDM switching and routing Quality of service Performance measurement and evaluation Next-generation optical networks: architecture, signaling, and control Traffic measurement and field trials Optical burst and packet switching OBS/OPS node architectures Burst/Packet scheduling and routing algorithms Contention resolution/avoidance strategies Services and applications for OBS/OPS (e.g., grid networks, storage-area networks, etc.) Burst assembly and ingress traffic shaping Hybrid OBS/TDM or OBS/wavelength routing Manuscript Submission To submit to this special issue, follow the normal procedure for submission to JON and select ``Photonics in Switching' in the features indicator of the online

Parasitic resistive switching uncovered from complementary resistive switching in single active-layer oxide memory device

Science.gov (United States)

Zhu, Lisha; Hu, Wei; Gao, Chao; Guo, Yongcai

2017-12-01

This paper reports the reversible transition processes between the bipolar and complementary resistive switching (CRS) characteristics on the binary metal-oxide resistive memory devices of Pt/HfO x /TiN and Pt/TaO x /TiN by applying the appropriate bias voltages. More interestingly, by controlling the amplitude of the negative bias, the parasitic resistive switching effect exhibiting repeatable switching behavior is uncovered from the CRS behavior. The electrical observation of the parasitic resistive switching effect can be explained by the controlled size of the conductive filament. This work confirms the transformation and interrelationship among the bipolar, parasitic, and CRS effects, and thus provides new insight into the understanding of the physical mechanism of the binary metal-oxide resistive switching memory devices.

Soft switching buck-boost converter for photovoltaic power generation; Taiyoko hatsuden no tame no soft switching shokoatsu converter

Energy Technology Data Exchange (ETDEWEB)

Lee, H. [Kyungnam University (Korea, Republic of)

1996-10-27

A soft switching method with small switching loss was proposed for the purpose of increasing the efficiency of a DC-DC boost converter which converted a DC current generated by solar cells to a variable DC current. Existing current converters are supplemented by using a snubber circuit around the switch so as to protect the switch by a hard switching action. However, with an increase of the output current, snubber loss is increased, reducing the efficiency. In order to solve this problem, the partial resonant switch method was applied to the converter; with this method of partially forming a resonant circuit only at the time of turning on/off of the switch, the switching loss was reduced through the soft switching, thereby making the proposed converter operate with high efficiency. Moreover, the resonant element of the partial resonant circuit using a snubber condenser, the energy accumulated in the condenser was regenerated on the power supply side without loss of snubber. With the regenerated energy, the proposed converter was provided with a smaller ratio of switching to use than the conventional converter. 4 refs., 7 figs., 1 tab.

Reversible switch between the nanoporous and the nonporous state of amphiphilic block copolymer films regulated by selective swelling.

Science.gov (United States)

Yan, Nina; Wang, Yong

2015-09-21

Switchable nanoporous films, which can repeatedly alternate their porosities, are of great interest in a diversity of fields. Currently these intelligent materials are mostly based on polyelectrolytes and their porosities can change only in relatively narrow ranges, typically under wet conditions, severely limiting their applications. Here we develop a new system, which is capable of reversibly switching between a highly porous state and a nonporous state dozens of times regulated simply by exposure to selective solvents. In this system nanopores are created or reversibly eliminated in films of a block copolymer, polystyrene-block-poly(2-vinyl pyridine) (PS-b-P2VP), by exposing the films to P2VP-selective or PS-selective solvents, respectively. The mechanism of the switch is based on the selective swelling of the constituent blocks in corresponding solvents, which is a nondestructive and easily controllable process enabling the repeatable and ample switch between the open and the closed state. Systematic microscopic and ellipsometric characterization methods are performed to elucidate the pore-closing course induced by nonsolvents and the cycling between the pore-open and the pore-closed state up to 20 times. The affinity of the solvent for PS blocks is found to play a dominating role in determining the pore-closing process and the porosities of the pore-open films increase with the cycling numbers as a result of loose packing conditions of the polymer chains. We finally demonstrate the potential applications of these films as intelligent antireflection coatings and drug carriers.

Design and construction of the advanced photon source 352-MHz rf system switching control

International Nuclear Information System (INIS)

Horan, D.; Solita, L.; Reigle, D.; Dimonte, N.

1997-01-01

A switching control system has been designed and built to provide the capability of rapidly switching the waveguide and low-level cabling between different klystrons to operate the Advanced Photon Source storage ring in the event of a failure of a klystron system or to perform necessary repairs and preventative maintenance. The twelve possible modes of operation allow for complete redundancy of the booster synchrotron rf system and either a maximum of two storage ring rf systems to be completely off-line or one system to be used as a power source for an rf test stand. A programmable controller is used to send commands to intermediate control panels which interface to WR2300 waveguide switches and phase shifters, rf cavity interlock and low-level rf distribution systems, and klystron power supply controls for rapid reconfiguration of the rf systems in response to a mode-selection command. Mode selection is a local manual operation using a keyswitch arrangement which prevents more than one mode from being selected at a time. The programmable controller also monitors for hardware malfunction and guards against open-quotes hot-switchingclose quotes of the rf systems. The rf switching controls system is monitored via the Experimental Physics and Industrial Control System (EPICS) for remote system status check

Robust Switching Control and Subspace Identification for Flutter of Flexible Wing

Directory of Open Access Journals (Sweden)

Yizhe Wang

2018-01-01

Full Text Available Active flutter suppression and subspace identification for a flexible wing model using micro fiber composite actuator were experimentally studied in a low speed wind tunnel. NACA0006 thin airfoil model was used for the experimental object to verify the performance of identification algorithm and designed controller. The equation of the fluid, vibration, and piezoelectric coupled motion was theoretically analyzed and experimentally identified under the open-loop and closed-loop condition by subspace method for controller design. A robust pole placement algorithm in terms of linear matrix inequality that accommodates the model uncertainty caused by identification deviation and flow speed variation was utilized to stabilize the divergent aeroelastic system. For further enlarging the flutter envelope, additional controllers were designed subject to the models beyond the flutter speed. Wind speed was measured online as the decision parameter of switching between the controllers. To ensure the stability of arbitrary switching, Common Lyapunov function method was applied to design the robust pole placement controllers for different models to ensure that the closed-loop system shared a common Lyapunov function. Wind tunnel result showed that the designed controllers could stabilize the time varying aeroelastic system over a wide range under arbitrary switching.

Non-fragile switched H∞ control for morphing aircraft with asynchronous switching

Directory of Open Access Journals (Sweden)

Haoyu CHENG

2017-06-01

Full Text Available This paper deals with the problem of non-fragile linear parameter-varying (LPV H∞ control for morphing aircraft with asynchronous switching. The switched LPV model of morphing aircraft is established by Jacobian linearization approach according to the nonlinear model. The data missing is taken into account in the link from sensors to controllers and the link from controllers to actuators, which satisfies Bernoulli distribution. The non-fragile switched LPV controllers are constructed with consideration of the uncertainties of controllers and asynchronous switching phenomenon. The parameter-dependent Lyapunov functional method and mode-dependent average dwell time (MDADT method are combined to guarantee the stability and prescribed performance of the system. The sufficient conditions on the solvability of the problem are derived in the form of linear matrix inequalities (LMI. In order to achieve higher efficiency of the designing process, an algorithm is applied to divide the whole set into subsets automatically. Simulation results are provided to verify the effectiveness and superiority of the method in the paper.

Sector switching among histopathologists in KwaZulu-Natal, South Africa: a qualitative study.

Science.gov (United States)

Ruggunan, Shaun D; Singh, Suveera

2013-05-30

The mobility of health care professionals from the public to private sector is prevalent in South Africa. However, literature on sector switching of clinical doctors remains limited. It is against this background that this study aims to make the labour market visible for histopathologists and identify the reasons for sector switching. This study is exploratory and descriptive. It uses qualitative methods, such as in-depth interviews, with 70% (n = 16/23) of the population of histopathologists in KwaZulu-Natal, South Africa. Lee's (1966) push-pull theory is adapted to explain the pull sector switching behaviours of histopathologists. Interviews were recorded and independently transcribed. The narratives of the participants were coded to reflect the main themes that contributed to their sector switching behaviours. Five key themes emerged as reasons for the mobility of histopathologists from the public to private sector in KwaZulu-Natal. The findings indicate that remuneration, working conditions, work flexibility, career pathing and autonomy of labour processes are the key drivers of this mobility. Histopathologists provide a core function in the health care chain. However, their invisibility in academic discourse in both public health and human resources for health indicates the paucity of research undertaken on the importance of these specialists in the health care chain. This is especially significant in developing countries like South Africa, where there is a dearth of these specialists. This study, while exploratory, aims to open a dialogue to better understand their reasons for sector switching and, hopefully, inform policies on training, recruitment and retention of these specialists.

Streamer model for high voltage water switches

International Nuclear Information System (INIS)

Sazama, F.J.; Kenyon, V.L. III

1979-01-01

An electrical switch model for high voltage water switches has been developed which predicts streamer-switching effects that correlate well with water-switch data from Casino over the past four years and with switch data from recent Aurora/AMP experiments. Preclosure rounding and postclosure resistive damping of pulseforming line voltage waveforms are explained in terms of spatially-extensive, capacitive-coupling of the conducting streamers as they propagate across the gap and in terms of time-dependent streamer resistance and inductance. The arc resistance of the Casino water switch and of a gas switch under test on Casino was determined by computer fit to be 0.5 +- 0.1 ohms and 0.3 +- 0.06 ohms respectively, during the time of peak current in the power pulse. Energy lost in the water switch during the first pulse is 18% of that stored in the pulseforming line while similar energy lost in the gas switch is 11%. The model is described, computer transient analyses are compared with observed water and gas switch data and the results - switch resistance, inductance and energy loss during the primary power pulse - are presented

Switching dynamics of TaOx-based threshold switching devices

Science.gov (United States)

Goodwill, Jonathan M.; Gala, Darshil K.; Bain, James A.; Skowronski, Marek

2018-03-01

Bi-stable volatile switching devices are being used as access devices in solid-state memory arrays and as the active part of compact oscillators. Such structures exhibit two stable states of resistance and switch between them at a critical value of voltage or current. A typical resistance transient under a constant amplitude voltage pulse starts with a slow decrease followed by a rapid drop and leveling off at a low steady state value. This behavior prompted the interpretation of initial delay and fast transition as due to two different processes. Here, we show that the entire transient including incubation time, transition time, and the final resistance values in TaOx-based switching can be explained by one process, namely, Joule heating with the rapid transition due to the thermal runaway. The time, which is required for the device in the conducting state to relax back to the stable high resistance one, is also consistent with the proposed mechanism.

Development of the switching components for ZT-40

International Nuclear Information System (INIS)

Melton, J.G.; Dike, R.S.; Hanks, K.W.; Nunnally, W.C.

1977-01-01

Switching of the main capacitor banks for ZT-40 will be accomplished by spark gap switches. Initially, there will be 576 start switches and 288 crowbar switches. A development program is under way to develop three switches; (1) a versatile start switch, which can be used for both the I/sub z/ and the I/sub theta/ capacitor banks, with a wide operating voltage range, (2) a crowbar switch which is capable of crowbarring the circuit without the power crowbar bank, and (3) a power crowbar switch, which can handle 50 to 100 coulombs, so that a large number of crowbar switches will not be required when the power crowbar circuit is added. The problems with the start switches and the first crowbar switch have been solved, or alleviated. The development of a power crowbar switch has just begun

Research and design of pulsed switching power supply for deep tumor therapy facility with heavy ions accelerator in Lanzhou

International Nuclear Information System (INIS)

Shi Chunfeng; Zhao Jiang; Yan Hongbin; Wu Fengjun; Gao Daqing

2012-01-01

The pulsed switching power supply was developed for deep tumor therapy facility with heavy ions in cooler-storage-ring of the heavy ions research facility in Lanzhou (HIRFL-CSR). The control principle of the dual closed-loop scheme was described and the open-loop Bode diagrams were given. The results of simulation and prototype experiment show that the current error gets much smaller than that of the single closed-loop pulsed switching power supply. Moreover, the simulation and test results were analyzed, and the circuit configuration and dual closed-loop strategy selected are practicable. (authors)

Switch mode power supply

International Nuclear Information System (INIS)

Kim, Hui Jun

1993-06-01

This book concentrates on switch mode power supply. It has four parts, which are introduction of switch mode power supply with DC-DC converter such as Buck converter boost converter, Buck-boost converter and PWM control circuit, explanation for SMPS with DC-DC converter modeling and power mode control, resonance converter like resonance switch, converter, multi resonance converter and series resonance and parallel resonance converters, basic test of SMPS with PWM control circuit, Buck converter, Boost converter, flyback converter, forward converter and IC for control circuit.

Demand Response of Thermostatic Loads by Optimized Switching-Fraction Broadcast

DEFF Research Database (Denmark)

Totu, Luminita Cristiana; Wisniewski, Rafal

2014-01-01

Demand response is an important Smart Grid concept that aims at facilitating the integration of volatile energy resources into the electricity grid. This paper considers the problem of managing large populations of thermostat-based devices with on/off operation. The objective is to enable demand...... Method is used to spatially discretize these equations. Next, a broadcast strategy with two switching-fraction signals is proposed for actuating the population. This is applied in an open-loop scenario for tracking a power reference by running an optimization with a multilinear objective....

A Polymerization-Associated Structural Switch in FtsZ That Enables Treadmilling of Model Filaments

Directory of Open Access Journals (Sweden)

James M. Wagstaff

2017-05-01

Full Text Available Bacterial cell division in many organisms involves a constricting cytokinetic ring that is orchestrated by the tubulin-like protein FtsZ. FtsZ forms dynamic filaments close to the membrane at the site of division that have recently been shown to treadmill around the division ring, guiding septal wall synthesis. Here, using X-ray crystallography of Staphylococcus aureus FtsZ (SaFtsZ, we reveal how an FtsZ can adopt two functionally distinct conformations, open and closed. The open form is found in SaFtsZ filaments formed in crystals and also in soluble filaments of Escherichia coli FtsZ as deduced by electron cryomicroscopy. The closed form is found within several crystal forms of two nonpolymerizing SaFtsZ mutants and corresponds to many previous FtsZ structures from other organisms. We argue that FtsZ’s conformational switch is polymerization-associated, driven by the formation of the longitudinal intersubunit interfaces along the filament. We show that such a switch provides explanations for both how treadmilling may occur within a single-stranded filament and why filament assembly is cooperative.

Chromatic interocular-switch rivalry.

Science.gov (United States)

Christiansen, Jens H; D'Antona, Anthony D; Shevell, Steven K

2017-05-01

Interocular-switch rivalry (also known as stimulus rivalry) is a kind of binocular rivalry in which two rivalrous images are swapped between the eyes several times a second. The result is stable periods of one image and then the other, with stable intervals that span many eye swaps (Logothetis, Leopold, & Sheinberg, 1996). Previous work used this close kin of binocular rivalry with rivalrous forms. Experiments here test whether chromatic interocular-switch rivalry, in which the swapped stimuli differ in only chromaticity, results in slow alternation between two colors. Swapping equiluminant rivalrous chromaticities at 3.75 Hz resulted in slow perceptual color alternation, with one or the other color often continuously visible for two seconds or longer (during which there were 15+ eye swaps). A well-known theory for sustained percepts from interocular-switch rivalry with form is inhibitory competition between binocular neurons driven by monocular neurons with matched orientation tuning in each eye; such binocular neurons would produce a stable response when a given orientation is swapped between the eyes. A similar model can account for the percepts here from chromatic interocular-switch rivalry and is underpinned by the neurophysiological finding that color-preferring binocular neurons are driven by monocular neurons from each eye with well-matched chromatic selectivity (Peirce, Solomon, Forte, & Lennie, 2008). In contrast to chromatic interocular-switch rivalry, luminance interocular-switch rivalry with swapped stimuli that differ in only luminance did not result in slowly alternating percepts of different brightnesses.

Optimization of multi-branch switched diversity systems

KAUST Repository

Nam, Haewoon; Alouini, Mohamed-Slim

2009-01-01

A performance optimization based on the optimal switching threshold(s) for a multi-branch switched diversity system is discussed in this paper. For the conventional multi-branch switched diversity system with a single switching threshold

A low-latency optical switch architecture using integrated μm SOI-based contention resolution and switching

Science.gov (United States)

Mourgias-Alexandris, G.; Moralis-Pegios, M.; Terzenidis, N.; Cherchi, M.; Harjanne, M.; Aalto, T.; Vyrsokinos, K.; Pleros, N.

2018-02-01

The urgent need for high-bandwidth and high-port connectivity in Data Centers has boosted the deployment of optoelectronic packet switches towards bringing high data-rate optics closer to the ASIC, realizing optical transceiver functions directly at the ASIC package for high-rate, low-energy and low-latency interconnects. Even though optics can offer a broad range of low-energy integrated switch fabrics for replacing electronic switches and seamlessly interface with the optical I/Os, the use of energy- and latency-consuming electronic SerDes continues to be a necessity, mainly dictated by the absence of integrated and reliable optical buffering solutions. SerDes undertakes the role of optimally synergizing the lower-speed electronic buffers with the incoming and outgoing optical streams, suggesting that a SerDes-released chip-scale optical switch fabric can be only realized in case all necessary functions including contention resolution and switching can be implemented on a common photonic integration platform. In this paper, we demonstrate experimentally a hybrid Broadcast-and-Select (BS) / wavelength routed optical switch that performs both the optical buffering and switching functions with μm-scale Silicon-integrated building blocks. Optical buffering is carried out in a silicon-integrated variable delay line bank with a record-high on-chip delay/footprint efficiency of 2.6ns/mm2 and up to 17.2 nsec delay capability, while switching is executed via a BS design and a silicon-integrated echelle grating, assisted by SOA-MZI wavelength conversion stages and controlled by a FPGA header processing module. The switch has been experimentally validated in a 3x3 arrangement with 10Gb/s NRZ optical data packets, demonstrating error-free switching operation with a power penalty of <5dB.

Untriggered water switching

International Nuclear Information System (INIS)

Van Devender, J.P.; Martin, T.H.

Recent experiments indicate that synchronous untriggered multichannel switching in water will permit the development of relatively simple, ultra-low impedance, short pulse, relativistic electron beam (REB) accelerators. These experiments resulted in the delivery of a 1.5 MV, 0.75 MA, 15 ns pulse into a two-ohm line with a current risetime of 2 x 10 14 A/sec. The apparatus consisted of a 3 MV Marx generator and a series of three 112 cm wide strip water lines separated by two edge-plane water-gap switches. The Marx generator charged the first line in less than 400 ns. The first switch then formed five or more channels. The second line was charged in 60 ns and broke down with 10 to 25 channels at a mean field of 1.6 MV/cm. The closure time of each spark channel along both switches was measured with a streak camera and showed low jitter. The resulting fast pulse line construction is simpler and should provide considerable costs savings from previous designs. Multiples of these low impedance lines in parallel can be employed to obtain power levels in the 10 14 W range for REB fusion studies. (U.S.)

Energy storage, compression, and switching. Vol. 2

International Nuclear Information System (INIS)

Nardi, V.; Bostick, W.H.; Sahlin, H.

1983-01-01

This book is a compilation of papers presented at the Second International Conference on Energy Storage, Compression, and Switching, which was held in order to assemble active researchers with a major interest in plasma physics, electron beams, electric and magnetic energy storage systems, high voltage and high current switches, free-electron lasers, and pellet implosion plasma focus. Topics covered include: Slow systems: 50-60 Hz machinery, homopolar generators, slow capacitors, inductors, and solid state switches; Intermediate systems: fast capacitor banks; superconducting storage and switching; gas, vacuum, and dielectric switching; nonlinear (magnetic) switching; imploding liners capacitors; explosive generators; and fuses; and Fast systems: Marx, Blumlein, oil, water, and pressurized water dielectrics; switches; magnetic insulation; electron beams; and plasmas

A level switch with a sound tube

OpenAIRE

赤池, 誠規

2017-01-01

Level switches are sensor with an electrical contact output at a specific liquid, powder or bulk level. Most of traditional level switches are not suitable for harsh environments. The level switch in this study connects a loudspeaker on top end of the sound tube. When liquid, powder or bulk closes bottom end of the sound tube, the level switch turns on. The level switch is suitable for harsh environments and easy to install. The aim of this study is to propose a level switch with a sound tube...

Superconductivity, energy storage and switching

International Nuclear Information System (INIS)

Laquer, H.L.

1974-01-01

The phenomenon of superconductivity can contribute to the technology of energy storage and switching in two distinct ways. On one hand the zero resistivity of the superconductor can produce essentially infinite time constants so that an inductive storage system can be charged from very low power sources. On the other hand, the recovery of finite resistivity in a normal-going superconducting switch can take place in extremely short times, so that a system can be made to deliver energy at a very high power level. Topics reviewed include: physics of superconductivity, limits to switching speed of superconductors, physical and engineering properties of superconducting materials and assemblies, switching methods, load impedance considerations, refrigeration economics, limitations imposed by present day and near term technology, performance of existing and planned energy storage systems, and a comparison with some alternative methods of storing and switching energy. (U.S.)

45° sign switching of effective exchange bias due to competing anisotropies in fully epitaxial Co3FeN/MnN bilayers

Science.gov (United States)

Hajiri, T.; Yoshida, T.; Filianina, M.; Jaiswal, S.; Borie, B.; Asano, H.; Zabel, H.; Kläui, M.

2018-01-01

We report an unusual angular-dependent exchange bias effect in ferromagnet/antiferromagnet bilayers, where both ferromagnet and antiferromagnet are epitaxially grown. Numerical model calculations predict an approximately 45° period for the sign switching of the exchange-bias field, depending on the ratio between magnetocrystalline anisotropy and exchange-coupling constant. The switching of the sign is indicative of a competition between a fourfold magnetocrystalline anisotropy of the ferromagnet and a unidirectional anisotropy field of the exchange coupling. This predicted unusual angular-dependent exchange bias and its magnetization switching process are confirmed by measurements on fully epitaxial Co3FeN/MnN bilayers by longitudinal and transverse magneto-optic Kerr effect magnetometry. These results provide a deeper understanding of the exchange coupling phenomena in fully epitaxial bilayers with tailored materials and open up a complex switching energy landscape engineering by anisotropies.

Optical Multidimensional Switching for Data Center Networks

DEFF Research Database (Denmark)

Kamchevska, Valerija

2017-01-01

. Software controlled switching using an on-chip integrated fiber switch is demonstrated and enabling of additional network functionalities such as multicast and optical grooming is experimentally confirmed. Altogether this work demonstrates the potential of optical switching technologies...... for the purpose of deploying optical switching within the network. First, the Hi-Ring data center architecture is proposed. It is based on optical multidimensional switching nodes that provide switching in hierarchically layered space, wavelength and time domain. The performance of the Hi-Ring architecture...... is evaluated experimentally and successful switching of both high capacity wavelength connections and time-shared subwavelengthconnections is demonstrated. Error-free performance is also achieved when transmitting 7 Tbit/s using multicore fiber, confirming the ability to scale the network. Moreover...

Pinning Synchronization of Switched Complex Dynamical Networks

Directory of Open Access Journals (Sweden)

Liming Du

2015-01-01

Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

The effect of switching cracks on the vibration of a continuous beam bridge subjected to moving vehicles

Science.gov (United States)

Fu, Chunyu

2015-03-01

During the service life of bridges, cracks can easily occur due to the dynamic loadings acting on them. These cracks may seriously affect the safety and serviceability of the bridges. Thus, this paper investigates the effect of these cracks on the vibration of a continuous beam bridge subjected to moving vehicles. The cracks are simulated by switching cracks, which can open and close fully instantaneously, and the beam behavior is considered as a sequence of linear states, each of which can be evaluated through a modal analysis. Special attention is paid to the analysis of the instant of crack switching, the linkage point of two adjacent linear states. The mode shapes and equation of motion corresponding to the new state after the switching are determined first. Next, the responses at the switching instant are recalculated. Finally, the beam displacement can be obtained by taking these responses as the initial condition. A numerical method is applied to investigate the validity of the proposed method, and the results show that the crack switching can result in higher accelerations, alter the slopes of the modal contributions to the displacement, and produce a new peak in the displacement history. During the resonance caused by a series of vehicles, the switching can reduce the first modal contribution to the resonance, but increase the second modal contribution. As a result, the resonant amplitude becomes smaller and the resonant mode changes.

Oil Stiction in Fast Switching Annular Seat Valves for Digital Displacement Fluid Power Machines

DEFF Research Database (Denmark)

Roemer, Daniel Beck; Johansen, Per; Pedersen, Henrik C.

2014-01-01

Digital Displacement (DD) fluid power machines utilizes electronically controlled seat valves connected to pressure chambers to obtain variable displacement with high operational efficiency and high bandwidth. To achieve high efficiency, fast valve switching is essential and all aspects related...... to the dynamic behaviour of the seat valves must be considered to optimize the machine efficiency. A significant effect influencing the valves switching performance is the presence of oil stiction when separating the contact surfaces in valve opening movement. This oil stiction force is limited by cavitation...... for low pressure levels, e.g. valves connected to the low pressure manifold, however for valves operated at higher pressure levels, the oil stiction force is dominating when the separating surfaces are close to contact. This paper presents an analytic solution to the oil stiction force for annular seat...

Anisotropic Babinet-Invertible Metasurfaces to Realize Transmission-Reflection Switching for Orthogonal Polarizations of Light

Science.gov (United States)

Nakata, Yosuke; Urade, Yoshiro; Okimura, Kunio; Nakanishi, Toshihiro; Miyamaru, Fumiaki; Takeda, Mitsuo Wada; Kitano, Masao

2016-10-01

The electromagnetic properties of an extremely thin metallic checkerboard drastically change from resonant reflection (transmission) to resonant transmission (reflection) when the local electrical conductivity at the interconnection points of the checkerboard is switched. To date, such critical transitions of metasurfaces have been applied only when they have fourfold rotational symmetry, and their application to polarization control, which requires anisotropy, has been unexplored. To overcome this applicability limitation and open up alternative pathways for dynamic deep-subwavelength polarization control by utilizing critical transitions of checkerboardlike metasurfaces, we introduce a universal class of anisotropic Babinet-invertible metasurfaces enabling transmission-reflection switching for each orthogonally polarized wave. As an application of anisotropic Babinet-invertible metasurfaces, we experimentally realize a reconfigurable terahertz polarizer whose transmitting axis can be dynamically rotated by 90°.

Wide Bandgap Extrinsic Photoconductive Switches

Energy Technology Data Exchange (ETDEWEB)

Sullivan, James S. [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Univ. of California, Davis, CA (United States)

2012-01-20

Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

Improved body weight and metabolic outcomes in overweight or obese psychiatric patients switched to amisulpride from other atypical antipsychotics.

Science.gov (United States)

Lin, Chao-Cheng; Bai, Ya-Mei; Wang, Ying-Chieh; Chen, Tzu-Ting; Lai, I-Ching; Chen, Jen-Yeu; Chen, Shiow-Yi; Gau, Susan S F; Liou, Ying-Jay

2009-12-01

Switching to a different second-generation antipsychotic (SGA) with a lower risk of weight gain is recommended for overweight or obese psychiatric patients undergoing SGA treatment. However, there have been no complete reports regarding the long-term metabolic effects of switching to amisulpride. In this open-label 1-year study, we investigated the effects on body weight and other metabolic profiles when psychiatric patients treated with another SGA were switched to amisulpride treatment. Forty-six schizophrenia or schizoaffective inpatients with a body mass index greater than 27 kg/m were enrolled in the switch group. These patients were cross-titrated to amisulpride treatment and followed up for 1 year prospectively. Another 46 inpatients matched with the baseline body mass index of those in the switch group were enrolled as the control group retrospectively. The results showed that the switch group had greater weight loss than the control group (7.80 +/- 6.67 vs 2.60 +/- 6.23 kg, respectively; repeated-measure analysis of variance, P < 0.0005). During the treatment course, the amisulpride-treated patients showed significantly decreased fasting triglyceride, total cholesterol, glucose, and insulin resistance levels; decreased diastolic blood pressure and pulse rate; and a significant increase in high-density lipoprotein cholesterol levels after switching to amisulpride (all with a P < 0.05). The prevalence of metabolic syndrome in amisulpride-treated patients also decreased significantly from 65.2% to 30.4% (McNemar test, P < 0.0005). These findings suggest that switching to amisulpride could be an effective treatment of overweight or obese psychiatric patients treated previously with other SGAs.

47 CFR 69.106 - Local switching.

Science.gov (United States)

2010-10-01

... foreign services that use local exchange switching facilities. (c) If end users of an interstate or... local exchange carriers shall establish rate elements for local switching as follows: (1) Price cap... use local exchange switching facilities for the provision of interstate or foreign services. The...

Proceedings of the switched power workshop

International Nuclear Information System (INIS)

Fernow, R.C.

1988-01-01

These proceedings contain most of the presentations given at a workshop on the current state of research in techniques for switched power acceleration. The proceedings are divided, as was the workshop itself, into two parts. Part 1, contains the latest results from a number of groups active in switched power research. The major topic here is a method for switching externally supplied power onto a transmission line. Advocates for vacuum photodiode switching, solid state switching, gas switching, and synthetic pulse generation are all presented. Other important areas of research described in this section concern: external electrical and laser pulsing systems; the properties of the created electromagnetic pulse; structures used for transporting the electromagnetic pulse to the region where the electron beam is located; and possible applications. Part 2 of the proceedings considers the problem of designing a high brightness electron gun using switched power as the power source. This is an important first step in demonstrating the usefulness of switched power techniques for accelerator physics. In addition such a gun could have immediate practical importance for advanced acceleration studies since the brightness could exceed that of present sources by several orders of magnitude. I would like to take this opportunity to thank Kathleen Tuohy and Patricia Tuttle for their assistance in organizing and running the workshop. Their tireless efforts contribute greatly to a very productive meeting

Light-Responsive Ion-Redistribution-Induced Resistive Switching in Hybrid Perovskite Schottky Junctions

KAUST Repository

Guan, Xinwei

2017-11-23

Hybrid Perovskites have emerged as a class of highly versatile functional materials with applications in solar cells, photodetectors, transistors, and lasers. Recently, there have also been reports on perovskite-based resistive switching (RS) memories, but there remain open questions regarding device stability and switching mechanism. Here, an RS memory based on a high-quality capacitor structure made of an MAPbBr3 (CH3NH3PbBr3) perovskite layer sandwiched between Au and indium tin oxide (ITO) electrodes is reported. Such perovskite devices exhibit reliable RS with an ON/OFF ratio greater than 103, endurance over 103 cycles, and a retention time of 104 s. The analysis suggests that the RS operation hinges on the migration of charged ions, most likely MA vacancies, which reversibly modifies the perovskite bulk transport and the Schottky barrier at the MAPbBr3/ITO interface. Such perovskite memory devices can also be fabricated on flexible polyethylene terephthalate substrates with high bendability and reliability. Furthermore, it is found that reference devices made of another hybrid perovskite MAPbI3 consistently exhibit filament-type switching behavior. This work elucidates the important role of processing-dependent defects in the charge transport of hybrid perovskites and provides insights on the ion-redistribution-based RS in perovskite memory devices.

Online Open Circuit Fault Diagnosis for Rail Transit Traction Converter Based on Object-Oriented Colored Petri Net Topology Reasoning

Directory of Open Access Journals (Sweden)

Lei Wang

2016-01-01

Full Text Available For online open circuit fault diagnosis of the traction converter in rail transit vehicles, conventional approaches depend heavily on component parameters and circuit layouts. For better universality and less parameter sensitivity during the diagnosis, this paper proposes a novel topology analysis approach to diagnose switching device open circuit failures. During the diagnosis, the topology is analyzed with fault reasoning mechanism, which is based on object-oriented Petri net (OOCPN. The OOCPN model takes in digitalized current inputs as fault signatures, and dynamical transitions between discrete switching states of a circuit with broken device are symbolized with the dynamical transitions of colored tokens in OOCPN. Such transitions simulate natural reasoning process of an expert’s brain during diagnosis. The dependence on component parameters and on circuit layouts is finally eliminated by such circuit topology reasoning process. In the last part, the proposed online reasoning and diagnosis process is exemplified with the case of a certain switching device failure in the power circuit of traction converter.

Resistance switching memory in perovskite oxides

International Nuclear Information System (INIS)

Yan, Z.B.; Liu, J.-M.

2015-01-01

The resistance switching behavior has recently attracted great attentions for its application as resistive random access memories (RRAMs) due to a variety of advantages such as simple structure, high-density, high-speed and low-power. As a leading storage media, the transition metal perovskite oxide owns the strong correlation of electrons and the stable crystal structure, which brings out multifunctionality such as ferroelectric, multiferroic, superconductor, and colossal magnetoresistance/electroresistance effect, etc. The existence of rich electronic phases, metal–insulator transition and the nonstoichiometric oxygen in perovskite oxide provides good platforms to insight into the resistive switching mechanisms. In this review, we first introduce the general characteristics of the resistance switching effects, the operation methods and the storage media. Then, the experimental evidences of conductive filaments, the transport and switching mechanisms, and the memory performances and enhancing methods of perovskite oxide based filamentary RRAM cells have been summarized and discussed. Subsequently, the switching mechanisms and the performances of the uniform RRAM cells associating with the carrier trapping/detrapping and the ferroelectric polarization switching have been discussed. Finally, the advices and outlook for further investigating the resistance switching and enhancing the memory performances are given

Clocking Scheme for Switched-Capacitor Circuits

DEFF Research Database (Denmark)

Steensgaard-Madsen, Jesper

1998-01-01

A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed.......A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed....

Manually operated coded switch

International Nuclear Information System (INIS)

Barnette, J.H.

1978-01-01

The disclosure related to a manually operated recodable coded switch in which a code may be inserted, tried and used to actuate a lever controlling an external device. After attempting a code, the switch's code wheels must be returned to their zero positions before another try is made

Manufacture of Radio Frequency Micromachined Switches with Annealing

Directory of Open Access Journals (Sweden)

Cheng-Yang Lin

2014-01-01

Full Text Available The fabrication and characterization of a radio frequency (RF micromachined switch with annealing were presented. The structure of the RF switch consists of a membrane, coplanar waveguide (CPW lines, and eight springs. The RF switch is manufactured using the complementary metal oxide semiconductor (CMOS process. The switch requires a post-process to release the membrane and springs. The post-process uses a wet etching to remove the sacrificial silicon dioxide layer, and to obtain the suspended structures of the switch. In order to improve the residual stress of the switch, an annealing process is applied to the switch, and the membrane obtains an excellent flatness. The finite element method (FEM software CoventorWare is utilized to simulate the stress and displacement of the RF switch. Experimental results show that the RF switch has an insertion loss of 0.9 dB at 35 GHz and an isolation of 21 dB at 39 GHz. The actuation voltage of the switch is 14 V.

Manufacture of radio frequency micromachined switches with annealing.

Science.gov (United States)

Lin, Cheng-Yang; Dai, Ching-Liang

2014-01-17

The fabrication and characterization of a radio frequency (RF) micromachined switch with annealing were presented. The structure of the RF switch consists of a membrane, coplanar waveguide (CPW) lines, and eight springs. The RF switch is manufactured using the complementary metal oxide semiconductor (CMOS) process. The switch requires a post-process to release the membrane and springs. The post-process uses a wet etching to remove the sacrificial silicon dioxide layer, and to obtain the suspended structures of the switch. In order to improve the residual stress of the switch, an annealing process is applied to the switch, and the membrane obtains an excellent flatness. The finite element method (FEM) software CoventorWare is utilized to simulate the stress and displacement of the RF switch. Experimental results show that the RF switch has an insertion loss of 0.9 dB at 35 GHz and an isolation of 21 dB at 39 GHz. The actuation voltage of the switch is 14 V.

Observer-Based Robust Control of Uncertain Switched Fuzzy Systems with Combined Switching Controller

Directory of Open Access Journals (Sweden)

Hong Yang

2013-01-01

Full Text Available The observer-based robust control for a class of switched fuzzy (SF time-delay systems involving uncertainties and external disturbances is investigated in this paper. A switched fuzzy system, which differs from existing ones, is firstly employed to describe a nonlinear system. Next, a combined switching controller is proposed. The designed controller based on the observer instead of the state information integrates the advantages of both the switching controllers and the supplementary controllers but eliminates their disadvantages. The proposed controller provides good performance during the transient period, and the chattering effect is removed when the system state approaches the origin. Sufficient condition for the solvability of the robust control problem is given for the case that the state of system is not available. Since convex combination techniques are used to derive the delay-independent criteria, some subsystems are allowed to be unstable. Finally, various comparisons of the elaborated examples are conducted to demonstrate the effectiveness of the proposed control design approach.

Synchronization in complex networks with switching topology

International Nuclear Information System (INIS)

Wang, Lei; Wang, Qing-guo

2011-01-01

This Letter investigates synchronization issues of complex dynamical networks with switching topology. By constructing a common Lyapunov function, we show that local and global synchronization for a linearly coupled network with switching topology can be evaluated by the time average of second smallest eigenvalues corresponding to the Laplacians of switching topology. This result is quite powerful and can be further used to explore various switching cases for complex dynamical networks. Numerical simulations illustrate the effectiveness of the obtained results in the end. -- Highlights: → Synchronization of complex networks with switching topology is investigated. → A common Lyapunov function is established for synchronization of switching network. → The common Lyapunov function is not necessary to monotonically decrease with time. → Synchronization is determined by the second smallest eigenvalue of its Laplacian. → Synchronization criterion can be used to investigate various switching cases.

Research and embedded implementation of Layer 3 switch

Science.gov (United States)

Song, Jin; Cheng, Zijing

2009-12-01

In the internetworking world, switches and routers have been deployed for workgroup and enterprise connectivity. In the past, switches mainly operated at Layer 2 (they were extensions of bridges), while routers were clearly Layer3 devices. Recently, the line has blurred and switches operating at Layer 3 are becoming more popular. This paper explains the Linux Bridge, Layer 2 Switches, Virtual LAN (VLAN) and Layer 3 Switches. The flow chart of Layer 3 switches and working routine related to Layer 3 switch technology were investigated in detail. This paper presents a new method to implement layer 3 switching that is entirely accomplished in software and is embedded implemented by code transplanting based on PowerPC 460GT platform.

Combining SDM-Based Circuit Switching with Packet Switching in a Router for On-Chip Networks

Directory of Open Access Journals (Sweden)

Angelo Kuti Lusala

2012-01-01

Full Text Available A Hybrid router architecture for Networks-on-Chip “NoC” is presented, it combines Spatial Division Multiplexing “SDM” based circuit switching and packet switching in order to efficiently and separately handle both streaming and best-effort traffic generated in real-time applications. Furthermore the SDM technique is combined with Time Division Multiplexing “TDM” technique in the circuit switching part in order to increase path diversity, thus improving throughput while sharing communication resources among multiple connections. Combining these two techniques allows mitigating the poor resource usage inherent to circuit switching. In this way Quality of Service “QoS” is easily provided for the streaming traffic through the circuit-switched sub-router while the packet-switched sub-router handles best-effort traffic. The proposed hybrid router architectures were synthesized, placed and routed on an FPGA. Results show that a practicable Network-on-Chip “NoC” can be built using the proposed router architectures. 7 × 7 mesh NoCs were simulated in SystemC. Simulation results show that the probability of establishing paths through the NoC increases with the number of sub-channels and has its highest value when combining SDM with TDM, thereby significantly reducing contention in the NoC.

On The Snubber Influence To The Switching And Conduction Losses In A Converter Using Switched Capacitor

Directory of Open Access Journals (Sweden)

Viorel DUGAN

2002-12-01

Full Text Available The paper deals to design and to compute the snubber parameters influence on the switching and conduction losses of the transistors (IGBT used as bidirectional switches in a converter with switched capacitor. The converter was modelled with difference equations, and the transistors during turn-on and turn-off processes were simulated by dynamically varying resistance models. The energy loss per switching, commutation time, the variation of the transistor voltage etc. and the influence of snubber parameters in each of these cases are shown in the context of a converter used as a 50Hz reactive power controller unit

High-voltage high-current triggering vacuum switch

International Nuclear Information System (INIS)

Alferov, D.F.; Bunin, R.A.; Evsin, D.V.; Sidorov, V.A.

2012-01-01

Experimental investigations of switching and breaking capacities of the new high current triggered vacuum switch (TVS) are carried out at various parameters of discharge current. It has been shown that the high current triggered vacuum switch TVS can switch repeatedly a current from units up to ten kiloampers with duration up to ten millisecond [ru

Sequential Effects in Deduction: Cost of Inference Switch

Science.gov (United States)

Milan, Emilio G.; Moreno-Rios, Sergio; Espino, Orlando; Santamaria, Carlos; Gonzalez-Hernandez, Antonio

2010-01-01

The task-switch paradigm has helped psychologists gain insight into the processes involved in changing from one activity to another. The literature has yielded consistent results about switch cost reconfiguration (abrupt offset in regular task-switch vs. gradual reduction in random task-switch; endogenous and exogenous components of switch cost;…

Aurora oil switch upgrade program

International Nuclear Information System (INIS)

Warren, T.

1989-03-01

This report describes the short pulse synchronization requirements, the original Aurora trigger scheme, and the PI/SNLA approach to improving the synchronization. It also describes the oil switching design study undertaken as the first phase of the program. A discussion of oil-switch closure analysis and the conceptual design motivated by this analysis are presented. This paper also describes the oil-switch trigger pulser tests required to validate the concept. This includes the design of the testing facility, a description of the test goals, and a discussion of the results. This paper finally describes oil-switch trigger pulser testing on one of the four Aurora Blumlein modules, which includes the hardware design and operation, the testing goals, hardware installation, and test results. 9 refs., 26 figs

Switch junction sequences in PMS2-deficient mice reveal a microhomology-mediated mechanism of Ig class switch recombination

Science.gov (United States)

Ehrenstein, Michael R.; Rada, Cristina; Jones, Anne-Marie; Milstein, César; Neuberger, Michael S.

2001-01-01

Isotype switching involves a region-specific, nonhomologous recombinational deletion that has been suggested to occur by nonhomologous joining of broken DNA ends. Here, we find increased donor/acceptor homology at switch junctions from PMS2-deficient mice and propose that class switching can occur by microhomology-mediated end-joining. Interestingly, although isotype switching and somatic hypermutation show many parallels, we confirm that PMS2 deficiency has no major effect on the pattern of nucleotide substitutions generated during somatic hypermutation. This finding is in contrast to MSH2 deficiency. With MSH2, the altered pattern of switch recombination and hypermutation suggests parallels in the mechanics of the two processes, whereas the fact that PMS2 deficiency affects only switch recombination may reflect differences in the pathways of break resolution. PMID:11717399

Ultra High-Speed Radio Frequency Switch Based on Photonics.

Science.gov (United States)

Ge, Jia; Fok, Mable P

2015-11-26

Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed switching property is achieved with the use of a rapidly tunable microwave photonic filter with tens of gigahertz frequency tuning speed, where the tuning mechanism is based on the ultra-fast electro-optics Pockels effect. The RF switch has a wide operation bandwidth of 12 GHz and can go up to 40 GHz, depending on the bandwidth of the modulator used in the scheme. The proposed RF switch can either work as an ON/OFF switch or a two-channel switch, tens of picoseconds switching speed is experimentally observed for both type of switches.

Compound semiconductor optical waveguide switch

Science.gov (United States)

Spahn, Olga B.; Sullivan, Charles T.; Garcia, Ernest J.

2003-06-10

An optical waveguide switch is disclosed which is formed from III-V compound semiconductors and which has a moveable optical waveguide with a cantilevered portion that can be bent laterally by an integral electrostatic actuator to route an optical signal (i.e. light) between the moveable optical waveguide and one of a plurality of fixed optical waveguides. A plurality of optical waveguide switches can be formed on a common substrate and interconnected to form an optical switching network.

Isolated converter with synchronized switching leg

NARCIS (Netherlands)

2003-01-01

An amplification device is disclosed providing a way of integrating a switch mode power supply and a class D amplifier (switch mode amplifier). This results in the usage of basically one magnetic component (1), one major energy storage element (4) and switches (20, 30) that are controlled in such a

45○ sign switching of effective exchange bias due to competing anisotropies in fully epitaxial Co3FeN/MnN bilayers.

Science.gov (United States)

Hajiri, Tetsuya; Yoshida, Takuya; Filianina, Mariia; Jaiswal, Samridh; Borie, Benjamin; Asano, H; Zabel, Hartmut; Klaui, Mathias

2017-11-20

We report an unusual angular-dependent exchange bias effect in ferromagnet/antiferromagnet bilayers, where both ferromagnet and antiferromagnet are epitaxially grown. Numerical model calculations predict an approximately 45$^\\circ$ period for the sign switching of the exchange-bias field, depending on the ratio between magnetocrystalline anisotropy and exchange-coupling constant. The switching of the sign is indicative of a competition between a fourfold magnetocrystalline anisotropy of the ferromagnet and a unidirectional anisotropy field of the exchange coupling. This predicted unusual angular-dependent exchange bias and its magnetization switching process are confirmed by measurements on fully epitaxial Co$_3$FeN/MnN bilayers by longitudinal and transverse magneto-optic Kerr effect magnetometry. These results provide a deeper understanding of the exchange coupling phenomena in fully epitaxial bilayers with tailored materials and open up a complex switching energy landscape engineering by anisotropies. © 2017 IOP Publishing Ltd.

The Water SWITCH-ON Spatial Information Platform (SIP)

Science.gov (United States)

Sala Calero, J., Sr.; Boot, G., Sr.; Dihé, P., Sr.; Arheimer, B.

2017-12-01

The amount of hydrological open data is continually growing and providing opportunities to the scientific community. Although the existing data portals (GEOSS Portal, INSPIRE community geoportal and others) enable access to open data, many users still find browsing through them difficult. Moreover, the time spent on gathering and preparing data usually is more significant than the time spent on the experiment itself. Thus, any improvement on searching, understanding, accessing or using open data is greatly beneficial. The Spatial Information Platform (SIP) has been developed to tackle these issues within the SWITCH-ON European Commission funded FP7 project. The SIP has been designed as a set of tools based on open standards that provide to the user all the necessary functionalities as described in the Publish-Find-Bind (PFB) pattern. In other words, this means that the SIP helps users to locate relevant and suitable data for their experiments analysis, to access and transform it (filtering, extraction, selection, conversion, aggregation). Moreover, the SIP can be used to provide descriptive information about the data and to publish it so others can find and use it. The SIP is based on existing open data protocols such as the OGC/CSW, OGC/WMS, OpenDAP and open-source components like PostgreSQL/PostGIS, GeoServer and pyCSW. The SIP is divided in three main user interfaces: the BYOD (Browse your open dataset) web interface, the Expert GUI tool and the Upload Data and Metadata web interface. The BYOD HTML5 client is the main entry point for users that want to browse through open data in the SIP. The BYOD has a map interface based on Leaflet JavaScript libraries so that the users can search more efficiently. The web-based Open Data Registration Tool is a user-friendly upload and metadata description interface (geographical extent, license, DOI generation). The Expert GUI is a desktop application that provides full metadata editing capabilities for the metadata

Reversible switching of fluorophore property based on intrinsic conformational transition of adenylate kinase during its catalytic cycle.

Science.gov (United States)

Fujii, Akira; Hirota, Shun; Matsuo, Takashi

2013-07-17

Adenylate kinase shows a conformational transition (OPEN and CLOSED forms) during substrate binding and product release to mediate the phosphoryl transfer between ADP and ATP/AMP. The protein motional characteristics will be useful to construct switching systems of fluorophore properties caused by the catalytic cycle of the enzyme. This paper demonstrates in situ reversible switching of a fluorophore property driven by the conformational transition of the enzyme. The pyrene-conjugated mutant adenylate kinase is able to switch the monomer/excimer emission property of pyrene on addition of ADP or P(1)P(5)-di(adenosine-5')pentaphosphate (Ap5A, a transition state analog). The observation under the dilute condition (~0.1 μM) indicates that the emission spectral change was caused by the motion of a protein molecule and not led by protein-protein interactions through π-π stacking of pyrene rings. The switching can be reversibly conducted by using hexokinase-coupling reaction. The fashion of the changes in emission intensities at various ligand concentrations is different between ADP, Mg(2+)-bound ADP, and Mg(2+)-bound Ap5A. The emission property switching is repeatable by a sequential addition of a substrate in a one-pot process. It is proposed that the property of a synthetic molecule on the enzyme surface is switchable in response to the catalytic cycle of adenylate kinase.

Wireless Nanoionic-Based Radio Frequency Switch

Science.gov (United States)

Nessel, James A. (Inventor); Miranda, Felix A (Inventor)

2017-01-01

A nanoionic switch connected to one or more rectenna modules is disclosed. The rectenna module is configured to receive a wireless signal and apply a first bias to change a state of the nanoionic switch from a first state to a second state. The rectenna module can receive a second wireless signal and apply a second bias to change the nanoionic switch from the second state back to the first state. The first bias is generally opposite of the first bias. The rectenna module accordingly permits operation of the nanoionic switch without onboard power.

Simplified design of switching power supplies

CERN Document Server

Lenk, John

1995-01-01

* Describes the operation of each circuit in detail * Examines a wide selection of external components that modify the IC package characteristics * Provides hands-on, essential information for designing a switching power supply Simplified Design of Switching Power Supplies is an all-inclusive, one-stop guide to switching power-supply design. Step-by-step instructions and diagrams render this book essential for the student and the experimenter, as well as the design professional. Simplified Design of Switching Power Supplies concentrates on the use of IC regulators. All popular forms of swit

Nanocrystalline Si pathway induced unipolar resistive switching behavior from annealed Si-rich SiN{sub x}/SiN{sub y} multilayers

Energy Technology Data Exchange (ETDEWEB)

Jiang, Xiaofan; Ma, Zhongyuan, E-mail: zyma@nju.edu.cn; Yang, Huafeng; Yu, Jie; Wang, Wen; Zhang, Wenping; Li, Wei; Xu, Jun; Xu, Ling; Chen, Kunji; Huang, Xinfan; Feng, Duan [National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory of Photonic Electronic Materials Sciences and Technology, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China)

2014-09-28

Adding a resistive switching functionality to a silicon microelectronic chip is a new challenge in materials research. Here, we demonstrate that unipolar and electrode-independent resistive switching effects can be realized in the annealed Si-rich SiN{sub x}/SiN{sub y} multilayers with high on/off ratio of 10{sup 9}. High resolution transmission electron microscopy reveals that for the high resistance state broken pathways composed of discrete nanocrystalline silicon (nc-Si) exist in the Si nitride multilayers. While for the low resistance state the discrete nc-Si regions is connected, forming continuous nc-Si pathways. Based on the analysis of the temperature dependent I-V characteristics and HRTEM photos, we found that the break-and-bridge evolution of nc-Si pathway is the origin of resistive switching memory behavior. Our findings provide insights into the mechanism of the resistive switching behavior in nc-Si films, opening a way for it to be utilized as a material in Si-based memories.

Switched reluctance motor drives

Indian Academy of Sciences (India)

Davis RM, Ray WF, Blake RJ 1981 Inverter drive for switched reluctance: circuits and component ratings. Inst. Elec. Eng. Proc. B128: 126-136. Ehsani M. 1991 Position Sensor elimination technique for the switched reluctance motor drive. US Patent No. 5,072,166. Ehsani M, Ramani K R 1993 Direct control strategies based ...

Seismic switch for strong motion measurement

Science.gov (United States)

Harben, P.E.; Rodgers, P.W.; Ewert, D.W.

1995-05-30

A seismic switching device is described that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period. 11 figs.

Optical computer switching network

Science.gov (United States)

Clymer, B.; Collins, S. A., Jr.

1985-01-01

The design for an optical switching system for minicomputers that uses an optical spatial light modulator such as a Hughes liquid crystal light valve is presented. The switching system is designed to connect 80 minicomputers coupled to the switching system by optical fibers. The system has two major parts: the connection system that connects the data lines by which the computers communicate via a two-dimensional optical matrix array and the control system that controls which computers are connected. The basic system, the matrix-based connecting system, and some of the optical components to be used are described. Finally, the details of the control system are given and illustrated with a discussion of timing.

Resistive switching: An investigation of the bipolar–unipolar transition in Co-doped ZnO thin films

International Nuclear Information System (INIS)

Santos, Daniel A.A.; Zeng, Hao; Macêdo, Marcelo A.

2015-01-01

Highlights: • A purely bipolar behavior on a Co-doped ZnO thin film has been demonstrated. • We have shown what can happen if a unipolar test is performed in a purely bipolar device. • An explanation for how a sample can show a purely bipolar switching behavior was suggested. • An important open issue about resistive switching effect was put in debate. - Abstract: In order to investigate the resistive switching effect we built devices in a planar structure in which two Al contacts were deposited on the top of the film and separated by a small gap using a shadow mask. Therefore, two samples of 10% Co-doped ZnO thin films were sputtered on glass substrate. High resolution X-ray diffraction (HRXRD) revealed a highly c-axis oriented crystalline structure, without secondary phase. The high resolution scanning electron microscopy (HRSEM) showed a flat surface with good coverage and thickness about 300 nm. A Keithley 2425 semiconductor characterization system was used to perform the resistive switching tests in the bipolar and unipolar modes. Considering only the effect of compliance current (CC), the devices showed a purely bipolar behavior since an increase in CC did not induce a transition to unipolar behavior

Switching to aripiprazole in outpatients with schizophrenia experiencing insufficient efficacy and/or safety/tolerability issues with risperidone: a randomized, multicentre, open-label study.

Science.gov (United States)

Ryckmans, V; Kahn, J P; Modell, S; Werner, C; McQuade, R D; Kerselaers, W; Lissens, J; Sanchez, R

2009-05-01

This study evaluated the safety/tolerability and effectiveness of aripiprazole titrated-dose versus fixed-dose switching strategies from risperidone in patients with schizophrenia experiencing insufficient efficacy and/or safety/tolerability issues. Patients were randomized to an aripiprazole titrated-dose (starting dose 5 mg/day) or fixed-dose (dose 15 mg/day) switching strategy with risperidone down-tapering. Primary endpoint was rate of discontinuation due to adverse events (AEs) during the 12-week study. Secondary endpoints included positive and negative syndrome scale (PANSS), clinical global impressions - improvement of illness scale (CGI-I), preference of medication (POM), subjective well-being under neuroleptics (SWN-K) and GEOPTE (Grupo Español para la Optimización del Tratamiento de la Esquizofrenia) scales. Rates of discontinuations due to AEs were similar between titrated-dose and fixed-dose strategies (3.5% vs. 5.0%; p=0.448). Improvements in mean PANSS total scores were similar between aripiprazole titrated-dose and fixed-dose strategies (-14.8 vs. -17.2; LOCF), as were mean CGI-I scores (2.9 vs. 2.8; p=0.425; LOCF) and SWN-K scores (+8.6 vs.+10.3; OC,+7.8 vs.+9.8; LOCF). Switching can be effectively and safely achieved through a titrated-dose or fixed-dose switching strategy for aripiprazole, with down-titration of risperidone.

Analysis on the Motivations of Code–Switching%Analysis on the Motivations of Code– Switching

Institute of Scientific and Technical Information of China (English)

孔祥曼

2015-01-01

Code-switching is a common phenomenon in language contact. It reflects the speaker's psychological state and his attitude towards a certain language or a language variety. This paper briefly analyzes the social and psychological motivations of the speakers when they use code-switching.

High-speed 2 × 2 silicon-based electro-optic switch with nanosecond switch time

International Nuclear Information System (INIS)

Xue-Jun, Xu; Shao-Wu, Chen; Hai-Hua, Xu; Yang, Sun; Yu-De, Yu; Jin-Zhong, Yu; Qi-Ming, Wang

2009-01-01

A 2 × 2 electro-optic switch is experimentally demonstrated using the optical structure of a Mach–Zehnder interferometer (MZI) based on a submicron rib waveguide and the electrical structure of a PIN diode on silicon-on-insulator (SOI). The switch behaviour is achieved through the plasma dispersion effect of silicon. The device has a modulation arm of 1 mm in length and cross-section of 400 nm×340 nm. The measurement results show that the switch has a V π L π figure of merit of 0.145 V·cm and the extinction ratios of two output ports and cross talk are 40 dB, 28 dB and −28 dB, respectively. A 3 dB modulation bandwidth of 90 MHz and a switch time of 6.8 ns for the rise edge and 2.7 ns for the fall edge are also demonstrated

Improved switch-resistor packaging

Science.gov (United States)

Redmerski, R. E.

1980-01-01

Packaging approach makes resistors more accessible and easily identified with specific switches. Failures are repaired more quickly because of improved accessibility. Typical board includes one resistor that acts as circuit breaker, and others are positioned so that their values can be easily measured when switch is operated. Approach saves weight by using less wire and saves valuable panel space.

A gain-coefficient switched Alexandrite laser

International Nuclear Information System (INIS)

Lee, Chris J; Van der Slot, Peter J M; Boller, Klaus-J

2013-01-01

We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

Secure videoconferencing equipment switching system and method

Science.gov (United States)

Hansen, Michael E [Livermore, CA

2009-01-13

A switching system and method are provided to facilitate use of videoconference facilities over a plurality of security levels. The system includes a switch coupled to a plurality of codecs and communication networks. Audio/Visual peripheral components are connected to the switch. The switch couples control and data signals between the Audio/Visual peripheral components and one but nor both of the plurality of codecs. The switch additionally couples communication networks of the appropriate security level to each of the codecs. In this manner, a videoconferencing facility is provided for use on both secure and non-secure networks.

Stochastic multistep polarization switching in ferroelectrics

Science.gov (United States)

Genenko, Y. A.; Khachaturyan, R.; Schultheiß, J.; Ossipov, A.; Daniels, J. E.; Koruza, J.

2018-04-01

Consecutive stochastic 90° polarization switching events, clearly resolved in recent experiments, are described by a nucleation and growth multistep model. It extends the classical Kolmogorov-Avrami-Ishibashi approach and includes possible consecutive 90°- and parallel 180° switching events. The model predicts the results of simultaneous time-resolved macroscopic measurements of polarization and strain, performed on a tetragonal Pb (Zr ,Ti ) O3 ceramic in a wide range of electric fields over a time domain of seven orders of magnitude. It allows the determination of the fractions of individual switching processes, their characteristic switching times, activation fields, and respective Avrami indices.

The increased importance of sector switching

DEFF Research Database (Denmark)

Frederiksen, Anders; Hansen, Jesper Rosenberg

2017-01-01

Sector switching is an important phenomenon that casts light on public–private differences. Yet our knowledge about its prevalence and trends is limited. We study sector switching using unique Danish register-based employer–employee data covering more than 25 years. We find that sector switching...... constitutes 18.5% of all job-to-job mobility, and the trend is increasing both from public to private and from private to public. Sector switching is also generally increasing for middle managers, but for administrative professionals only the flows from private to public increase and for top managers only...... the flows from public to private increase....

Detecting MOV stem to stem-nut lubricant degradation by reviewing MOV open-quotes seating timeclose quotes

International Nuclear Information System (INIS)

Loweth, W.A.

1996-01-01

The objective is to describe a methodology, suitable for IST Programs, that obtains sufficient data to assess and trend the overall condition of AC and DC MOVs. Using existing diagnostic test equipment, recording the time from Hard Seat Contact to the Torque Switch Trip point (TST), open-quote Seating Time (msec)close quotes, can provide a means to quickly detect for signs of lubricant degradation in the interface between the stem and stem-nut for MOVs. Obtaining and trending the open-quote Seating Time close-quote parameter can be easily accomplished using the sensors which provide motor current, torque or thrust. From the initial baseline test to subsequent tests, it is the change in time between Hard Seat Contact to Torque Switch Trip point that is utilized to monitor changes in the coefficient of friction between the stem and stem-nut. While many Licensees have begun their MOV Periodic Verification Programs, obtaining the open-quotes Seating Timeclose quotes during Refueling Outages and comparing the results from subsequent outages can be an input to the justification for changing the MOV baseline test frequency

Balancing Absorptive Capacity and Inbound Open Innovation for Sustained Innovative Performance

DEFF Research Database (Denmark)

Bongsun, Kim; Kim, Eonsoo; Foss, Nicolai Juul

2016-01-01

How can a firm develop new ideas and turn them into profitable innovations on a sustained basis? We address this fundamental issue in a novel way by developing an integrative framework of absorptive capacity (AC) and inbound open innovation that is rooted in the attention-based view of the firm. We...... specifically address why a balance between open and closed innovation is important from the perspective of absorptive capacity, and show how it may be brought about. Pursuing either open or closed inbound innovation alone may result in an imbalance between potential AC and realized AC as well as inward......-looking AC and outward-looking AC, which will hinder innovative performance.We argue that practicing open and closed inbound innovation repeatedly and alternately by switching organizational attentions, and thus developing the associated AC, can facilitate balancing absorptive capacity and lead to innovative...

DETERMINANT OF DOWNWARD AUDITOR SWITCHING

Directory of Open Access Journals (Sweden)

Totok Budisantoso

2017-12-01

Full Text Available Abstract: Determinant of Downward Auditor Switching. This study examines the factors that influence downward auditor switching in five ASEAN countries. Fixed effect logistic regression was used as analytical method. This study found that opinion shopping occurred in ASEAN, especially in distress companies. Companies with complex businesses will retain the Big Four auditors to reduce complexity and audit costs. Audit and public committees serve as guardians of auditor quality. On the other hand, shareholders failed to maintain audit quality. It indicates that there is entrenchment effect in auditor switching.

Contraceptive method switching in the United States.

Science.gov (United States)

Grady, William R; Billy, John O G; Klepinger, Daniel H

2002-01-01

Switching among contraceptive method types is the primary determinant of the prevalence of use of specific contraceptive methods, and it has direct implications for women's ability to avoid unintended pregnancies. Yet, method switching among U.S. women has received little attention from researchers. Data from the 1995 National Survey of Family Growth were used to construct multiple-decrement life tables to explore the gross switching rates of married and unmarried women. Within each group, discrete-time hazard models were estimated to determine how women's characteristics affect their switching behavior. Overall rates of method switching are high among both married and unmarried women (40% and 61%, respectively). Married women's two-year switching rates vary from 30% among women who use the implant, injectable, IUD or other reversible methods to 43% among nonusers, while unmarried women's rates vary from 33% among women who use the implant, injectable or IUD to 70% among nonusers. Multivariate analyses of method switching according to women's characteristics indicate that among married women, women without children are less likely than other women to adopt sterilization or a long-term reversible contraceptive (the implant, injectable or IUD). Older married women have a higher rate than their younger counterparts of switching to sterilization, but are also more likely to continue using no method. Among unmarried women, younger and more highly educated women have high rates of switching to the condom and to dual methods. Women's method switching decisions may be driven primarily by concerns related to level and duration of contraceptive effectiveness, health risks associated with contraceptive use and, among single women, sexually transmitted disease prevention.

Households' switching behavior between electricity suppliers in Sweden

Energy Technology Data Exchange (ETDEWEB)

Ek, Kristina; Soederholm, Patrik [Economics Unit, Luleaa University of Technology, 971 87 Luleaa (Sweden)

2008-12-15

The overall purpose of this paper is to analyze the factors affecting households' decisions to: (a) switch to a new electricity supplier; and (b) actively renegotiate the electricity contract with the prevailing supplier. The study is based on 536 survey responses from Swedish households and they are analyzed econometrically using probit regression techniques. The analysis is based on a theoretical framework, which embraces both economic and psychological motives behind household decision-making. The results show that households that anticipate significant economic benefits from choosing a more active behavior are also more likely to purse this, while those with smaller potential gains (e.g., households without electric heating) are less likely to change supplier and/or renegotiate their contracts. The impact of overall electricity costs and knowledge about these is particularly important for the latter decision, while respondents that perceive relatively high search and information costs are less likely to switch to an alternative electricity supplier. Moreover, constraints on time, attention, and the ability to process information, may lead to optimizing analyses being replaced by imprecise routines and rules of thumb, and the benefits of the status quo appear to represent one of those simplifying rules. This also opens up for other influences on households' activity such as social interaction and media discourses that raise the attention level. Our results show that these influences are more likely to affect households' choice to switch to new service providers, i.e., the one area of the two investigated here that put the most demand on people's ability to search for and process information. (author)

A Novel Silicon-based Wideband RF Nano Switch Matrix Cell and the Fabrication of RF Nano Switch Structures

Directory of Open Access Journals (Sweden)

Yi Xiu YANG

2011-12-01

Full Text Available This paper presents the concept of RF nano switch matrix cell and the fabrication of RF nano switch. The nano switch matrix cell can be implemented into complex switch matrix for signal routing. RF nano switch is the decision unit for the matrix cell; in this research, it is fabricated on a tri-layer high-resistivity-silicon substrate using surface micromachining approach. Electron beam lithography is introduced to define the pattern and IC compatible deposition process is used to construct the metal layers. Silicon-based nano switch fabricated by IC compatible process can lead to a high potential of system integration to perform a cost effective system-on-a-chip solution. In this paper, simulation results of the designed matrix cell are presented; followed by the details of the nano structure fabrication and fabrication challenges optimizations; finally, measurements of the fabricated nano structure along with analytical discussions are also discussed.

Gas adsorption/absorption heat switch, phase 1

Science.gov (United States)

Chan, C. K.

1987-01-01

The service life and/or reliability of far-infrared sensors on surveillance satellites is presently limited by the cryocooler. The life and/or reliability, however, can be extended by using redundant cryocoolers. To reduce parasitic heat leak, each stage of the inactive redundant cryocooler must be thermally isolated from the optical system, while each stage of the active cryocooler must be thermally connected to the system. The thermal break or the thermal contact can be controlled by heat switches. Among different physical mechanisms for heat switching, mechanically activated heat switches tend to have low reliability and, furthermore, require a large contact force. Magnetoresistive heat switches are, except at very low temperatures, of very low efficiency. Heat switches operated by the heat pipe principle usually require a long response time. A sealed gas gap heat switch operated by an adsorption pump has no mechanical motion and should provide the reliability and long lifetime required in long-term space missions. Another potential application of a heat switch is the thermal isolation of the optical plane during decontamination.

Reluctance motor employing superconducting magnetic flux switches

International Nuclear Information System (INIS)

Spyker, R.L.; Ruckstadter, E.J.

1992-01-01

This paper reports that superconducting flux switches controlling the magnetic flux in the poles of a motor will enable the implementation of a reluctance motor using one central single phase winding. A superconducting flux switch consists of a ring of superconducting material surrounding a ferromagnetic pole of the motor. When in the superconducting state the switch will block all magnetic flux attempting to flow in the ferromagnetic core. When switched to the normal state the superconducting switch will allow the magnetic flux to flow freely in that pole. By using one high turns-count coil as a flux generator, and selectively channeling flux among the various poles using the superconducting flux switch, 3-phase operation can be emulated with a single-hase central AC source. The motor will also operate when the flux generating coil is driven by a DC current, provided the magnetic flux switches see a continuously varying magnetic flux. Rotor rotation provides this varying flux due to the change in stator pole inductance it produces

Pulsed laser triggered high speed microfluidic switch

Science.gov (United States)

Wu, Ting-Hsiang; Gao, Lanyu; Chen, Yue; Wei, Kenneth; Chiou, Pei-Yu

2008-10-01

We report a high-speed microfluidic switch capable of achieving a switching time of 10 μs. The switching mechanism is realized by exciting dynamic vapor bubbles with focused laser pulses in a microfluidic polydimethylsiloxane (PDMS) channel. The bubble expansion deforms the elastic PDMS channel wall and squeezes the adjacent sample channel to control its fluid and particle flows as captured by the time-resolved imaging system. A switching of polystyrene microspheres in a Y-shaped channel has also been demonstrated. This ultrafast laser triggered switching mechanism has the potential to advance the sorting speed of state-of-the-art microscale fluorescence activated cell sorting devices.

Study of the Switching Errors in an RSFQ Switch by Using a Computerized Test Setup

International Nuclear Information System (INIS)

Kim, Se Hoon; Baek, Seung Hun; Yang, Jung Kuk; Kim, Jun Ho; Kang, Joon Hee

2005-01-01

The problem of fluctuation-induced digital errors in a rapid single flux quantum (RSFQ) circuit has been a very important issue. In this work, we calculated the bit error rate of an RSFQ switch used in superconductive arithmetic logic unit (ALU). RSFQ switch should have a very low error rate in the optimal bias. Theoretical estimates of the RSFQ error rate are on the order of 10 -50 per bit operation. In this experiment, we prepared two identical circuits placed in parallel. Each circuit was composed of 10 Josephson transmission lines (JTLs) connected in series with an RSFQ switch placed in the middle of the 10 JTLs. We used a splitter to feed the same input signal to both circuits. The outputs of the two circuits were compared with an RSFQ exclusive OR (XOR) to measure the bit error rate of the RSFQ switch. By using a computerized bit-error-rate test setup, we measured the bit error rate of 2.18 x 10 -12 when the bias to the RSFQ switch was 0.398 mA that was quite off from the optimum bias of 0.6 mA.

Hydrogen-peroxide-modified egg albumen for transparent and flexible resistive switching memory

Science.gov (United States)

Zhou, Guangdong; Yao, Yanqing; Lu, Zhisong; Yang, Xiude; Han, Juanjuan; Wang, Gang; Rao, Xi; Li, Ping; Liu, Qian; Song, Qunliang

2017-10-01

Egg albumen is modified by hydrogen peroxide with concentrations of 5%, 10%, 15% and 30% at room temperature. Compared with devices without modification, a memory cell of Ag/10% H2O2-egg albumen/indium tin oxide exhibits obviously enhanced resistive switching memory behavior with a resistance ratio of 104, self-healing switching endurance for 900 cycles and a prolonged retention time for a 104 s @ 200 mV reading voltage after being bent 103 times. The breakage of massive protein chains occurs followed by the recombination of new protein chain networks due to the oxidation of amidogen and the synthesis of disulfide during the hydrogen peroxide modifying egg albumen. Ions such as Fe3+, Na+, K+, which are surrounded by protein chains, are exposed to the outside of protein chains to generate a series of traps during the egg albumen degeneration process. According to the fitting results of the double logarithm I-V curves and the current-sensing atomic force microscopy (CS-AFM) images of the ON and OFF states, the charge transfer from one trap center to its neighboring trap center is responsible for the resistive switching memory phenomena. The results of our work indicate that hydrogen- peroxide-modified egg albumen could open up a new avenue of biomaterial application in nanoelectronic systems.

Stochastic Switching Dynamics

DEFF Research Database (Denmark)

Simonsen, Maria

This thesis treats stochastic systems with switching dynamics. Models with these characteristics are studied from several perspectives. Initially in a simple framework given in the form of stochastic differential equations and, later, in an extended form which fits into the framework of sliding...... mode control. It is investigated how to understand and interpret solutions to models of switched systems, which are exposed to discontinuous dynamics and uncertainties (primarily) in the form of white noise. The goal is to gain knowledge about the performance of the system by interpreting the solution...

Monitoring Mellanox Infiniband SX6036 switches

CERN Document Server

Agapiou, Marinos

2017-01-01

The SX6036 switches addressed by my project, are part of a fully non-blocking fat-tree cluster consisting of 72 servers and 6 Mellanox SX6036 Infiniband switches. My project is about retrieving the appropriate metrics from the Infiniband switch cluster, ingesting the data to Collectd and after my data are being transfered to CERN Database, they are being visualized via Grafana Dashboards.

Optical switches based on surface plasmons

International Nuclear Information System (INIS)

Chen Cong; Wang Pei; Yuan Guanghui; Wang Xiaolei; Min Changjun; Deng Yan; Lu Yonghua; Ming Hai

2008-01-01

Great attention is being paid to surface plasmons (SPs) because of their potential applications in sensors, data storage and bio-photonics. Recently, more and more optical switches based on surface plasmon effects have been demonstrated either by simulation or experimentally. This article describes the principles, advantages and disadvantages of various types of optical switches based on SPs, in particular the all-optical switches. (authors)

A new switched power linac structure

International Nuclear Information System (INIS)

Villa, F.

1989-03-01

A new pulse power structure has been described that utilizes an easily accessible rectilinear switch. The new structure is more ''forgiving'' (as far as risetime is concerned) than the radial line transformer, and contains fewer switching structures/unit length. The combination of the new structure with the switch proposed seems to offer interesting possibilities for a future linear collider. 13 refs., 6 figs., 2 tabs

Polarization switching and patterning in self-assembled peptide tubular structures

Science.gov (United States)

Bdikin, Igor; Bystrov, Vladimir; Delgadillo, Ivonne; Gracio, José; Kopyl, Svitlana; Wojtas, Maciej; Mishina, Elena; Sigov, Alexander; Kholkin, Andrei L.

2012-04-01

Self-assembled peptide nanotubes are unique nanoscale objects that have great potential for a multitude of applications, including biosensors, nanotemplates, tissue engineering, biosurfactants, etc. The discovery of strong piezoactivity and polar properties in aromatic dipeptides [A. Kholkin, N. Amdursky, I. Bdikin, E. Gazit, and G. Rosenman, ACS Nano 4, 610 (2010)] opened up a new perspective for their use as biocompatible nanoactuators, nanomotors, and molecular machines. Another, as yet unexplored functional property is the ability to switch polarization and create artificial polarization patterns useful in various electronic and optical applications. In this work, we demonstrate that diphenylalanine peptide nanotubes are indeed electrically switchable if annealed at a temperature of about 150 °C. The new orthorhombic antipolar structure that appears after annealing allows for the existence of a radial polarization component, which is directly probed by piezoresponse force microscopy (PFM) measurements. Observation of the relatively stable polarization patterns and hysteresis loops via PFM testifies to the local reorientation of molecular dipoles in the radial direction. The experimental results are complemented with rigorous molecular calculations and create a solid background of electric-field induced deformation of aromatic rings and corresponding polarization switching in this emergent material.

Switching the Fermilab Accelerator Control System to a relational database

International Nuclear Information System (INIS)

Shtirbu, S.

1993-01-01

The accelerator control system (open-quotes ACNETclose quotes) at Fermilab is using a made-in-house, Assembly language, database. The database holds device information, which is mostly used for finding out how to read/set devices and how to interpret alarms. This is a very efficient implementation, but it lacks the needed flexibility and forces applications to store data in private/shared files. This database is being replaced by an off-the-shelf relational database (Sybase 2 ). The major constraints on switching are the necessity to maintain/improve response time and to minimize changes to existing applications. Innovative methods are used to help achieve the required performance, and a layer seven gateway simulates the old database for existing programs. The new database is running on a DEC ALPHA/VMS platform, and provides better performance. The switch is also exposing problems with the data currently stored in the database, and is helping in cleaning up erroneous data. The flexibility of the new relational database is going to facilitate many new applications in the future (e.g. a 3D presentation of device location). The new database is expected to fully replace the old database during this summer's shutdown

Photo-stimulated resistive switching of ZnO nanorods

International Nuclear Information System (INIS)

Park, Jinjoo; Lee, Seunghyup; Yong, Kijung

2012-01-01

Resistive switching memory devices are promising candidates for emerging memory technologies because they yield outstanding device performance. Storage mechanisms for achieving high-density memory applications have been developed; however, so far many of them exhibit typical resistive switching behavior from the limited controlling conditions. In this study, we introduce photons as an unconventional stimulus for activating resistive switching behaviors. First, we compare the resistive switching behavior in light and dark conditions to describe how resistive switching memories can benefit from photons. Second, we drive the switching of resistance not by the electrical stimulus but only by the modulation of photon. ZnO nanorods were employed as a model system to demonstrate photo-stimulated resistive switching in high-surface-area nanomaterials, in which photo-driven surface states strongly affect their photoconductivity and resistance states. (paper)

Proton-Controlled Organic Microlaser Switch.

Science.gov (United States)

Gao, Zhenhua; Zhang, Wei; Yan, Yongli; Yi, Jun; Dong, Haiyun; Wang, Kang; Yao, Jiannian; Zhao, Yong Sheng

2018-05-25

Microscale laser switches have been playing irreplaceable roles in the development of photonic devices with high integration levels. However, it remains a challenge to switch the lasing wavelengths across a wide range due to relatively fixed energy bands in traditional semiconductors. Here, we report a strategy to switch the lasing wavelengths among multiple states based on a proton-controlled intramolecular charge-transfer (ICT) process in organic dye-doped flexible microsphere resonant cavities. The protonic acids can effectively bind onto the ICT molecules, which thus enhance the ICT strength of the dyes and lead to a red-shifted gain behavior. On this basis, the gain region was effectively modulated by using acids with different proton-donating ability, and as a result, laser switching among multiple wavelengths was achieved. The results will provide guidance for the rational design of miniaturized lasers with performances based on the characteristic of organic optoelectronic materials.

Multi-planed unified switching topologies

Science.gov (United States)

Chen, Dong; Heidelberger, Philip; Sugawara, Yutaka

2017-07-04

An apparatus and method for extending the scalability and improving the partitionability of networks that contain all-to-all links for transporting packet traffic from a source endpoint to a destination endpoint with low per-endpoint (per-server) cost and a small number of hops. An all-to-all wiring in the baseline topology is decomposed into smaller all-to-all components in which each smaller all-to-all connection is replaced with star topology by using global switches. Stacking multiple copies of the star topology baseline network creates a multi-planed switching topology for transporting packet traffic. Point-to-point unified stacking method using global switch wiring methods connects multiple planes of a baseline topology by using the global switches to create a large network size with a low number of hops, i.e., low network latency. Grouped unified stacking method increases the scalability (network size) of a stacked topology.

Low prepulse, high power density water dielectric switching

International Nuclear Information System (INIS)

Johnson, D.L.; VanDevender, J.P.; Martin, T.H.

1979-01-01

Prepulse voltage suppression has proven difficult in high power, high voltage accelerators employing self-breakdown water dielectric switches. A novel and cost effective water switch has been developed at Sandia Laboratories which reduces prepulse voltage by reducing the capacity across the switch. This prepulse suppression switch causes energy formerly stored in the switch capacity and dissipated in the arc to be useful output energy. The switching technique also allows the pulse forming lines to be stacked in parallel and electrically isolated from the load after the line has been discharged. The switch consists of a ground plane, with several holes, inserted between the switch electrodes. The output line switch electrodes extend through the holes and face electrodes on the pulse forming line (PFL). The capacity between the PFL and the output transmission line is reduced by about 80%. The gap spacing between the output line electrode and the hole in the ground plane is adjusted so that breakdown occurs after the main pulse and provides a crow bar between the load and the source. Performance data from the Proto II, Mite and Ripple test facilities are presented

Architecture Design and Experimental Platform Demonstration of Optical Network based on OpenFlow Protocol

Science.gov (United States)

Xing, Fangyuan; Wang, Honghuan; Yin, Hongxi; Li, Ming; Luo, Shenzi; Wu, Chenguang

2016-02-01

With the extensive application of cloud computing and data centres, as well as the constantly emerging services, the big data with the burst characteristic has brought huge challenges to optical networks. Consequently, the software defined optical network (SDON) that combines optical networks with software defined network (SDN), has attracted much attention. In this paper, an OpenFlow-enabled optical node employed in optical cross-connect (OXC) and reconfigurable optical add/drop multiplexer (ROADM), is proposed. An open source OpenFlow controller is extended on routing strategies. In addition, the experiment platform based on OpenFlow protocol for software defined optical network, is designed. The feasibility and availability of the OpenFlow-enabled optical nodes and the extended OpenFlow controller are validated by the connectivity test, protection switching and load balancing experiments in this test platform.

Outlook for the use of microsecond plasma opening switches to generate high-power nanosecond current pulses

International Nuclear Information System (INIS)

Dolgachev, G.I.; Maslennikov, D.D.; Ushakov, A.G.

2006-01-01

Paper deals with a phenomenon of current breaking in a conducting plasma volume of plasma opening switchers with a nanosecond time of energy initiation and their application in high-power generators. One determined the conditions to ensure megavolt voltages under the erosion mode making use of external applied magnetic field to ensure magnetic insulation of gap of plasma opening switchers. One studied the peculiar features of application of plasma opening switchers under 5-6 MV voltages to ensure X-ray and gamma-radiation pulses [ru

High-explosive driven crowbar switch

International Nuclear Information System (INIS)

Dike, R.S.; Kewish, R.W. Jr.

1976-01-01

The disclosure relates to a compact explosive driven switch for use as a low resistance, low inductance crowbar switch. A high-explosive charge extrudes a deformable conductive metallic plate through a polyethylene insulating layer to achieve a hard current contact with a supportive annular conductor

Switched-mode power supply apparatus and method

NARCIS (Netherlands)

2013-01-01

The present invention relates to a switched-mode power supply apparatus and a corresponding method. For an effective compensation of non-linearities caused by dead- time and voltage drops in the switching power amplifier of the apparatus, an apparatus is proposed comprising a switching power

Switched-mode power supply apparatus and method

NARCIS (Netherlands)

2013-01-01

The present invention relates to a switched-mode power supply apparatus and a corresponding method. For an effective compensation of non-linearities caused by dead-time and voltage drops in the switching power amplifier of the apparatus, an apparatus is proposed comprising a switching power

Control and synchronisation in switched arrival systems

NARCIS (Netherlands)

Rem, B.; Armbruster, H.D.

2003-01-01

A chaotic model of a production flow called the switched arrival system is extended to include switching times and maintenance. The probability distribution of the chaotic return times is calculated. Scheduling maintenance, loss of production due to switching, and control of the chaotic dynamics is

Switching away from pipotiazine palmitate: a naturalistic study.

Science.gov (United States)

Mustafa, Feras Ali

2017-01-01

In March 2015, pipotiazine palmitate depot antipsychotic was globally withdrawn due to the shortage of its active ingredient. Thus, all patients receiving this medication had to be switched to an alternative antipsychotic drug. In this study we set to evaluate the process of switching away from pipotiazine palmitate within our clinical service, and its impact on hospitalization. Demographic and clinical data on patients who were receiving pipotiazine palmitate in Northamptonshire at the time of its withdrawal were anonymously extracted from their electronic records and analyzed using descriptive statistics. A total of 17 patients were switched away from pipotiazine palmitate at the time of its withdrawal, all of whom had a prior history of nonadherence with oral treatment. A total of 14 patients were switched to another depot antipsychotic drug, while three patients chose an oral alternative which they subsequently discontinued resulting in relapse and hospitalization. There was a five-fold increase in mean hospitalization among patients who completed a year after the switch. Switching away from pipotiazine palmitate was associated with significant clinical deterioration in patients who switched to an oral antipsychotic, whereas most patients who switched to another depot treatment maintained stability. Clinicians should exercise caution when switching patients with schizophrenia away from depot antipsychotic drugs, especially in cases of patients with a history of treatment nonadherence who prefer to switch to oral antipsychotics.

Interallelic class switch recombination contributes significantly to class switching in mouse B cells.

Science.gov (United States)

Reynaud, Stéphane; Delpy, Laurent; Fleury, Laurence; Dougier, Hei-Lanne; Sirac, Christophe; Cogné, Michel

2005-05-15

Except for the expression of IgM and IgD, DNA recombination is constantly needed for the expression of other Ig classes and subclasses. The predominant path of class switch recombination (CSR) is intrachromosomal, and the looping-out and deletion model has been abundantly documented. However, switch regions also occasionally constitute convenient substrates for interchromosomal recombination, since it is noticeably the case in a number of chromosomal translocations causing oncogene deregulation in the course of lymphoma and myeloma. Although asymmetric accessibility of Ig alleles should theoretically limit its occurrence, interallelic CSR was shown to occur at low levels during IgA switching in rabbit, where the definition of allotypes within both V and C regions helped identify interchromosomally derived Ig. Thus, we wished to evaluate precisely interallelic CSR frequency in mouse B cells, by using a system in which only one allele (of b allotype) could express a functional VDJ region, whereas only interallelic CSR could restore expression of an excluded (a allotype) allele. In our study, we show that interchromosomal recombination of V(H) and Cgamma or Calpha occurs in vivo in B cells at a frequency that makes a significant contribution to physiological class switching: trans-association of V(H) and C(H) genes accounted for 7% of all alpha mRNA, and this frequency was about twice higher for the gamma3 transcripts, despite the much shorter distance between the J(H) region and the Cgamma3 gene, thus confirming that this phenomenon corresponded to site-specific switching and not to random recombination between long homologous loci.

The Application of High Temperature Superconducting Materials to Power Switches

CERN Document Server

March, S A; Ballarino, A

2009-01-01

Superconducting switches may find application in superconducting magnet systems that require energy extraction. Such superconducting switches could be bypass-switches that are operated in conjunction with a parallel resistor or dump-switches where all of the energy is dissipated in the switch itself. Bypass-switches are more suited to higher energy circuits as a portion of the energy can be dissipated in the external dump resistor. Dump- switches require less material and triggering energy as a lower switch resistance is needed to achieve the required total dump resistance. Both superconducting bypass-switches and superconducting dump-switches can be ther- mally activated. Switching times that are comparable to those obtained with mechanical bypass-switch systems can be achieved using a co-wound heater that is powered by a ca- pacitor discharge. Switches that have fast thermal diffusion times through the insulation can be modelled as a lumped system whereas those with slow thermal diffusion times were modelle...

Detecting MOV stem to stem-nut lubricant degradation by reviewing MOV {open_quotes}seating time{close_quotes}

Energy Technology Data Exchange (ETDEWEB)

Loweth, W.A.

1996-12-01

The objective is to describe a methodology, suitable for IST Programs, that obtains sufficient data to assess and trend the overall condition of AC and DC MOVs. Using existing diagnostic test equipment, recording the time from Hard Seat Contact to the Torque Switch Trip point (TST), {open_quote}Seating Time (msec){close_quotes}, can provide a means to quickly detect for signs of lubricant degradation in the interface between the stem and stem-nut for MOVs. Obtaining and trending the {open_quote}Seating Time{close_quote} parameter can be easily accomplished using the sensors which provide motor current, torque or thrust. From the initial baseline test to subsequent tests, it is the change in time between Hard Seat Contact to Torque Switch Trip point that is utilized to monitor changes in the coefficient of friction between the stem and stem-nut. While many Licensees have begun their MOV Periodic Verification Programs, obtaining the {open_quotes}Seating Time{close_quotes} during Refueling Outages and comparing the results from subsequent outages can be an input to the justification for changing the MOV baseline test frequency.

Behavioral plasticity through the modulation of switch neurons.

Science.gov (United States)

Vassiliades, Vassilis; Christodoulou, Chris

2016-02-01

A central question in artificial intelligence is how to design agents capable of switching between different behaviors in response to environmental changes. Taking inspiration from neuroscience, we address this problem by utilizing artificial neural networks (NNs) as agent controllers, and mechanisms such as neuromodulation and synaptic gating. The novel aspect of this work is the introduction of a type of artificial neuron we call "switch neuron". A switch neuron regulates the flow of information in NNs by selectively gating all but one of its incoming synaptic connections, effectively allowing only one signal to propagate forward. The allowed connection is determined by the switch neuron's level of modulatory activation which is affected by modulatory signals, such as signals that encode some information about the reward received by the agent. An important aspect of the switch neuron is that it can be used in appropriate "switch modules" in order to modulate other switch neurons. As we show, the introduction of the switch modules enables the creation of sequences of gating events. This is achieved through the design of a modulatory pathway capable of exploring in a principled manner all permutations of the connections arriving on the switch neurons. We test the model by presenting appropriate architectures in nonstationary binary association problems and T-maze tasks. The results show that for all tasks, the switch neuron architectures generate optimal adaptive behaviors, providing evidence that the switch neuron model could be a valuable tool in simulations where behavioral plasticity is required. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mechanism of single atom switch on silicon

DEFF Research Database (Denmark)

Quaade, Ulrich; Stokbro, Kurt; Thirstrup, C.

1998-01-01

We demonstrate single atom switch on silicon which operates by displacement of a hydrogen atom on the silicon (100) surface at room temperature. We find two principal effects by which the switch is controlled: a pronounced maximum of the switching probability as function of sample bias...

Caffeine improves anticipatory processes in task switching

NARCIS (Netherlands)

Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials

Denoising of genetic switches based on Parrondo's paradox

Science.gov (United States)

Fotoohinasab, Atiyeh; Fatemizadeh, Emad; Pezeshk, Hamid; Sadeghi, Mehdi

2018-03-01

Random decision making in genetic switches can be modeled as tossing a biased coin. In other word, each genetic switch can be considered as a game in which the reactive elements compete with each other to increase their molecular concentrations. The existence of a very small number of reactive element molecules has caused the neglect of effects of noise to be inevitable. Noise can lead to undesirable cell fate in cellular differentiation processes. In this paper, we study the robustness to noise in genetic switches by considering another switch to have a new gene regulatory network (GRN) in which both switches have been affected by the same noise and for this purpose, we will use Parrondo's paradox. We introduce two networks of games based on possible regulatory relations between genes. Our results show that the robustness to noise can increase by combining these noisy switches. We also describe how one of the switches in network II can model lysis/lysogeny decision making of bacteriophage lambda in Escherichia coli and we change its fate by another switch.

Exploring the repetition bias in voluntary task switching.

Science.gov (United States)

Mittelstädt, Victor; Dignath, David; Schmidt-Ott, Magdalena; Kiesel, Andrea

2018-01-01

In the voluntary task-switching paradigm, participants are required to randomly select tasks. We reasoned that the consistent finding of a repetition bias (i.e., participants repeat tasks more often than expected by chance) reflects reasonable adaptive task selection behavior to balance the goal of random task selection with the goals to minimize the time and effort for task performance. We conducted two experiments in which participants were provided with variable amount of preview for the non-chosen task stimuli (i.e., potential switch stimuli). We assumed that switch stimuli would initiate some pre-processing resulting in improved performance in switch trials. Results showed that reduced switch costs due to extra-preview in advance of each trial were accompanied by more task switches. This finding is in line with the characteristics of rational adaptive behavior. However, participants were not biased to switch tasks more often than chance despite large switch benefits. We suggest that participants might avoid effortful additional control processes that modulate the effects of preview on task performance and task choice.

Multiuser switched diversity scheduling schemes

KAUST Repository

Shaqfeh, Mohammad; Alnuweiri, Hussein M.; Alouini, Mohamed-Slim

2012-01-01

Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

Charge transport through molecular switches

International Nuclear Information System (INIS)

Jan van der Molen, Sense; Liljeroth, Peter

2010-01-01

We review the fascinating research on charge transport through switchable molecules. In the past decade, detailed investigations have been performed on a great variety of molecular switches, including mechanically interlocked switches (rotaxanes and catenanes), redox-active molecules and photochromic switches (e.g. azobenzenes and diarylethenes). To probe these molecules, both individually and in self-assembled monolayers (SAMs), a broad set of methods have been developed. These range from low temperature scanning tunneling microscopy (STM) via two-terminal break junctions to larger scale SAM-based devices. It is generally found that the electronic coupling between molecules and electrodes has a profound influence on the properties of such molecular junctions. For example, an intrinsically switchable molecule may lose its functionality after it is contacted. Vice versa, switchable two-terminal devices may be created using passive molecules ('extrinsic switching'). Developing a detailed understanding of the relation between coupling and switchability will be of key importance for both future research and technology. (topical review)

Charge transport through molecular switches

Energy Technology Data Exchange (ETDEWEB)

Jan van der Molen, Sense [Kamerlingh Onnes Laboratorium, Leiden University, Niels Bohrweg 2, 2333 CA Leiden (Netherlands); Liljeroth, Peter, E-mail: molen@physics.leidenuniv.n [Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, University of Utrecht, PO Box 80000, 3508 TA Utrecht (Netherlands)

2010-04-07

We review the fascinating research on charge transport through switchable molecules. In the past decade, detailed investigations have been performed on a great variety of molecular switches, including mechanically interlocked switches (rotaxanes and catenanes), redox-active molecules and photochromic switches (e.g. azobenzenes and diarylethenes). To probe these molecules, both individually and in self-assembled monolayers (SAMs), a broad set of methods have been developed. These range from low temperature scanning tunneling microscopy (STM) via two-terminal break junctions to larger scale SAM-based devices. It is generally found that the electronic coupling between molecules and electrodes has a profound influence on the properties of such molecular junctions. For example, an intrinsically switchable molecule may lose its functionality after it is contacted. Vice versa, switchable two-terminal devices may be created using passive molecules ('extrinsic switching'). Developing a detailed understanding of the relation between coupling and switchability will be of key importance for both future research and technology. (topical review)

Wide Bandgap Extrinsic Photoconductive Switches

Energy Technology Data Exchange (ETDEWEB)

Sullivan, James S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2013-07-03

Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6HSiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductive switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators.

Intrinsic nanofilamentation in resistive switching

KAUST Repository

Wu, Xing

2013-03-15

Resistive switching materials are promising candidates for nonvolatile data storage and reconfiguration of electronic applications. Intensive studies have been carried out on sandwiched metal-insulator-metal structures to achieve high density on-chip circuitry and non-volatile memory storage. Here, we provide insight into the mechanisms that govern highly reproducible controlled resistive switching via a nanofilament by using an asymmetric metal-insulator-semiconductor structure. In-situ transmission electron microscopy is used to study in real-time the physical structure and analyze the chemical composition of the nanofilament dynamically during resistive switching. Electrical stressing using an external voltage was applied by a tungsten tip to the nanosized devices having hafnium oxide (HfO2) as the insulator layer. The formation and rupture of the nanofilaments result in up to three orders of magnitude change in the current flowing through the dielectric during the switching event. Oxygen vacancies and metal atoms from the anode constitute the chemistry of the nanofilament.

Multiuser switched diversity scheduling schemes

KAUST Repository

Shaqfeh, Mohammad

2012-09-01

Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

Conceptual design of a high-speed electromagnetic switch for a modified flux-coupling-type SFCL and its application in renewable energy system.

Science.gov (United States)

Chen, Lei; Chen, Hongkun; Yang, Jun; Shu, Zhengyu; He, Huiwen; Shu, Xin

2016-01-01

The modified flux-coupling-type superconducting fault current (SFCL) is a high-efficient electrical auxiliary device, whose basic function is to suppress the short-circuit current by controlling the magnetic path through a high-speed switch. In this paper, the high-speed switch is based on electromagnetic repulsion mechanism, and its conceptual design is carried out to promote the application of the modified SFCL. Regarding that the switch which is consisting of a mobile copper disc, two fixed opening and closing coils, the computational method for the electromagnetic force is discussed, and also the dynamic mathematical model including circuit equation, magnetic field equation as well as mechanical motion equation is theoretically deduced. According to the mathematical modeling and calculation of characteristic parameters, a feasible design scheme is presented, and the high-speed switch's response time can be less than 0.5 ms. For that the modified SFCL is equipped with this high-speed switch, the SFCL's application in a 10 kV micro-grid system with multiple renewable energy sources are assessed in the MATLAB software. The simulations are well able to affirm the SFCL's performance behaviors.

Switch-attention (aka switch-reference in South-American temporal clauses: facilitating oral transmission

Directory of Open Access Journals (Sweden)

Rik van Gijn

2012-01-01

Full Text Available Cultures without a written tradition depend entirely on the oral channel to transmit sometimes highly complex information. It is therefore not surprising that in the languages of such cultures linguistic devices evolve that enhance textual coherence, and thus comprehension. These devices should ideally also be economical in terms of morphosyntactic complexity in order to facilitate both production and comprehension. In this paper, I will argue that switch-attention (a term preferred over the traditional switch-reference systems in temporal clauses fulfill these requirements of cohesion and complexity reduction, making them particularly apt for orally transmitting texts. Moreover, switch-reference systems seem to diffuse relatively easily. These features taken together are suggested to be (partly responsible for the widely attested phenomenon in areas without a lengthy written tradition.

Modeling and analysis of the Rimfire gas switch

International Nuclear Information System (INIS)

Gahl, John M.; Kemp, Mark A.; Struve, Kenneth William; Curry, Randy D.; McDonald, Ken F.

2005-01-01

Many accelerators at Sandia National Laboratories utilize the Rimfire gas switch for high-voltage, high-power switching. Future accelerators will have increased performance requirements for switching elements. When designing improved versions of the Rimfire switch, there is a need for quick and accurate simulation of the electrical effects of geometry changes. This paper presents an advanced circuit model of the Rimfire switch that can be used for these simulations. The development of the model is shown along with comparisons to past models and experimental results.

A CW Gunn diode bistable switching element.

Science.gov (United States)

Hurtado, M.; Rosenbaum, F. J.

1972-01-01

Experiments with a current-controlled bistable switching element using a CW Gunn diode are reported. Switching rates of the order of 10 MHz have been obtained. Switching is initiated by current pulses of short duration (5-10 ns). Rise times of the order of several nanoseconds could be obtained.

Average contraction and synchronization of complex switched networks

International Nuclear Information System (INIS)

Wang Lei; Wang Qingguo

2012-01-01

This paper introduces an average contraction analysis for nonlinear switched systems and applies it to investigating the synchronization of complex networks of coupled systems with switching topology. For a general nonlinear system with a time-dependent switching law, a basic convergence result is presented according to average contraction analysis, and a special case where trajectories of a distributed switched system converge to a linear subspace is then investigated. Synchronization is viewed as the special case with all trajectories approaching the synchronization manifold, and is thus studied for complex networks of coupled oscillators with switching topology. It is shown that the synchronization of a complex switched network can be evaluated by the dynamics of an isolated node, the coupling strength and the time average of the smallest eigenvalue associated with the Laplacians of switching topology and the coupling fashion. Finally, numerical simulations illustrate the effectiveness of the proposed methods. (paper)

Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch

Science.gov (United States)

Nessel, James; Miranda, Felix

2013-01-01

A new nonvolatile nanoionic switch is powered and controlled through wireless radio-frequency (RF) transmission. A thin layer of chalcogenide glass doped with a metal ion, such as silver, comprises the operational portion of the switch. For the switch to function, an oxidizable electrode is made positive (anode) with respect to an opposing electrode (cathode) when sufficient bias, typically on the order of a few tenths of a volt or more, is applied. This action causes the metal ions to flow toward the cathode through a coordinated hopping mechanism. At the cathode, a reduction reaction occurs to form a metal deposit. This metal deposit creates a conductive path that bridges the gap between electrodes to turn the switch on. Once this conductive path is formed, no further power is required to maintain it. To reverse this process, the metal deposit is made positive with respect to the original oxidizable electrode, causing the dissolution of the metal bridge thereby turning the switch off. Once the metal deposit has been completely dissolved, the process self-terminates. This switching process features the following attributes. It requires very little to change states (i.e., on and off). Furthermore, no power is required to maintain the states; hence, the state of the switch is nonvolatile. Because of these attributes the integration of a rectenna to provide the necessary power and control is unique to this embodiment. A rectenna, or rectifying antenna, generates DC power from an incident RF signal. The low voltages and power required for the nanoionic switch control are easily generated from this system and provide the switch with a novel capability to be operated and powered from an external wireless device. In one realization, an RF signal of a specific frequency can be used to set the switch into an off state, while another frequency can be used to set the switch to an on state. The wireless, miniaturized, and nomoving- part features of this switch make it

Manufacturing fuel-switching capability, 1988

International Nuclear Information System (INIS)

1991-09-01

Historically, about one-third of all energy consumed in the United States has been used by manufacturers. About one-quarter of manufacturing energy is used as feedstocks and raw material inputs that are converted into nonenergy products; the remainder is used for its energy content. During 1988, the most recent year for which data are available, manufacturers consumed 15.5 quadrillion British thermal units (Btu) of energy to produce heat and power and to generate electricity. The manufacturing sector also has widespread capabilities to switch from one fuel to another for either economic or emergency reasons. There are numerous ways to define fuel switching. For the purposes of the Manufacturing Energy Consumption Survey (MECS), fuel switching is defined as the capability to substitute one energy source for another within 30 days with no significant modifications to the fuel-consuming equipment, while keeping production constant. Fuel-switching capability allows manufacturers substantial flexibility in choosing their mix of energy sources. The consumption of a given energy source can be maximized if all possible switching into that energy source takes place. The estimates in this report are based on data collected on the 1988 Manufacturing Energy Consumption Survey (MECS), Forms 846 (A through C). The EIA conducts this national sample survey of manufacturing energy consumption on a triennial basis. The MECS is the only comprehensive source of national-level data on energy-related information for the manufacturing industries. The MECS was first conducted in 1986 to collect data for 1985. This report presents information on the fuel-switching capabilities of manufacturers in 1988. This report is the second of a series based on the 1988 MECS. 8 figs., 31 tabs

Manufacturing fuel-switching capability, 1988

Energy Technology Data Exchange (ETDEWEB)

1991-09-01

Historically, about one-third of all energy consumed in the United States has been used by manufacturers. About one-quarter of manufacturing energy is used as feedstocks and raw material inputs that are converted into nonenergy products; the remainder is used for its energy content. During 1988, the most recent year for which data are available, manufacturers consumed 15.5 quadrillion British thermal units (Btu) of energy to produce heat and power and to generate electricity. The manufacturing sector also has widespread capabilities to switch from one fuel to another for either economic or emergency reasons. There are numerous ways to define fuel switching. For the purposes of the Manufacturing Energy Consumption Survey (MECS), fuel switching is defined as the capability to substitute one energy source for another within 30 days with no significant modifications to the fuel-consuming equipment, while keeping production constant. Fuel-switching capability allows manufacturers substantial flexibility in choosing their mix of energy sources. The consumption of a given energy source can be maximized if all possible switching into that energy source takes place. The estimates in this report are based on data collected on the 1988 Manufacturing Energy Consumption Survey (MECS), Forms 846 (A through C). The EIA conducts this national sample survey of manufacturing energy consumption on a triennial basis. The MECS is the only comprehensive source of national-level data on energy-related information for the manufacturing industries. The MECS was first conducted in 1986 to collect data for 1985. This report presents information on the fuel-switching capabilities of manufacturers in 1988. This report is the second of a series based on the 1988 MECS. 8 figs., 31 tabs.

RF-MEMS capacitive switches with high reliability

Science.gov (United States)

Goldsmith, Charles L.; Auciello, Orlando H.; Carlisle, John A.; Sampath, Suresh; Sumant, Anirudha V.; Carpick, Robert W.; Hwang, James; Mancini, Derrick C.; Gudeman, Chris

2013-09-03

A reliable long life RF-MEMS capacitive switch is provided with a dielectric layer comprising a "fast discharge diamond dielectric layer" and enabling rapid switch recovery, dielectric layer charging and discharging that is efficient and effective to enable RF-MEMS switch operation to greater than or equal to 100 billion cycles.

Analysis of Switched-Rigid Floating Oscillator

Directory of Open Access Journals (Sweden)

Prabhakar R. Marur

2009-01-01

Full Text Available In explicit finite element simulations, a technique called deformable-to-rigid (D2R switching is used routinely to reduce the computation time. Using the D2R option, the deformable parts in the model can be switched to rigid and reverted back to deformable when needed during the analysis. The time of activation of D2R however influences the overall dynamics of the system being analyzed. In this paper, a theoretical basis for the selection of time of rigid switching based on system energy is established. A floating oscillator problem is investigated for this purpose and closed-form analytical expressions are derived for different phases in rigid switching. The analytical expressions are validated by comparing the theoretical results with numerical computations.

A dynamic switching strategy for air-conditioning systems operated in light-thermal-load conditions

International Nuclear Information System (INIS)

Lin, Jin-Long; Yeh, T.-J.; Hwang, Wei-Yang

2009-01-01

Recently, modern air-conditioners have begun to incorporate variable-speed compressors and variable-opening expansion valves, together with feedback control to improve the performance and energy efficiency. However, for the compressor there usually exists a low-speed limit below which its speed can not be continuously modulated unless it is completely turned off. When the air-conditioning system is operated in light-thermal-load conditions, the low-speed limit causes the compressor to run in an on-off manner which can significantly degrade the performance and efficiency. In this paper, a dynamic switching strategy is proposed for such scenarios. The strategy is basically an integration of a cascading control structure, an intuitive switching strategy, and a dynamic compensator. While the control structure provides the nominal performance, the intuitive switching strategy and the dynamic compensator together can account for the compressor's low-speed limitation. Theoretical analysis reveals that when the output matrix of the dynamic compensator is chosen properly, the proposed strategy can effectively reduce the output error caused by the on-off operation of the compressor. Experiments also demonstrate that the proposed strategy can simultaneously provide better regulation for the indoor temperature and improve the energy efficiency at steady state.

Optical cross-connect circuit using hitless wavelength selective switch.

Science.gov (United States)

Goebuchi, Yuta; Hisada, Masahiko; Kato, Tomoyuki; Kokubun, Yasuo

2008-01-21

We have proposed and demonstrated the basic elements of a full matrix optical switching circuit (cross-connect circuit) using a hitless wavelength selective switch (WSS). The cross-connect circuits are made of a multi-wavelength channel selective switch consisting of cascaded hitless WSSs, and a multi-port switch. These switching elements are realized through the individual Thermo-Optic (TO) tuning of a series-coupled microring resonator, and can switch arbitrary wavelength channels without blocking other wavelength channels during tuning. We demonstrate a four wavelength selective switch using a parallel topology of double series coupled microring resonators and a three wavelength selective switch using a parallel topology of quadruple series coupled microring resonators. Since the spectrum shape of quadruple series coupled microring is much more box-like than the double series, a high extinction ratio of 39.0-46.6 dB and low switching cross talk of 19.3-24.5 dB were achieved.

Ultrafast pulse generation in photoconductive switches

DEFF Research Database (Denmark)

Keil, Ulrich Dieter Felix; Dykaar, D. R.

1996-01-01

Carrier and field dynamics in photoconductive switches are investigated by electrooptic sampling and voltage-dependent reflectivity measurements. We show that the nonuniform field distribution due to the two-dimensional nature of coplanar photoconductive switches, in combination with the large di...... difference in the mobilities of holes and electrons, determine the pronounced polarity dependence. Our measurements indicate that the pulse generation mechanism is a rapid voltage breakdown across the photoconductive switch and not a local field breakdown...

An absorptive single-pole four-throw switch using multiple-contact MEMS switches and its application to a monolithic millimeter-wave beam-forming network

International Nuclear Information System (INIS)

Lee, Sanghyo; Kim, Jong-Man; Kim, Yong-Kweon; Kwon, Youngwoo

2009-01-01

In this paper, a new absorptive single-pole four-throw (SP4T) switch based on multiple-contact switching is proposed and integrated with a Butler matrix to demonstrate a monolithic beam-forming network at millimeter waves (mm waves). In order to simplify the switching driving circuit and reduce the number of unit switches in an absorptive SP4T switch, the individual switches were replaced with long-span multiple-contact switches using stress-free single-crystalline-silicon MEMS technology. This approach improves the mechanical stability as well as the manufacturing yield, thereby allowing successful integration into a monolithic beam former. The fabricated absorptive SP4T MEMS switch shows insertion loss less than 1.3 dB, return losses better than 11 dB at 30 GHz and wideband isolation performance higher than 39 dB from 20 to 40 GHz. The absorptive SP4T MEMS switch is integrated with a 4 × 4 Butler matrix on a single chip to implement a monolithic beam-forming network, directing beam into four distinct angles. Array factors from the measured data show that the proposed absorptive SPnT MEMS switch can be effectively used for high-performance mm-wave beam-switching systems. This work corresponds to the first demonstration of a monolithic beam-forming network using switched beams

Analytical Modeling and Simulation of Four-Switch Hybrid Power Filter Working with Sixfold Switching Symmetry

Czech Academy of Sciences Publication Activity Database

Tlustý, J.; Škramlík, Jiří; Švec, J.; Valouch, Viktor

2012-01-01

Roč. 2012, č. 292178 (2012), s. 1-17 ISSN 1024-123X Institutional support: RVO:61388998 Keywords : analytical modeling * four-switch hybrid power filter * sixfold switching symmetry Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.383, year: 2012 http://www.hindawi.com/journals/mpe/2012/292178/

The double switch for atrioventricular discordance.

Science.gov (United States)

Brawn, William J

2005-01-01

Conventional surgery for atrioventricular discordance usually associated with ventricular arterial discordance leaves the morphologic right ventricle in the systemic circulation. Long-term follow-up results with this approach reveal a high incidence of right ventricular failure. The double switch procedure was introduced to restore the morphologic left ventricle to the systemic circulation. This operation is performed in two main ways: the atrial-arterial switch and the atrial switch plus Rastelli procedure. This double switch approach has been successful at least in the medium term in abolishing morphologic right ventricular failure and its associated tricuspid valve regurgitation. In the atrial-arterial switch group, there is an incidence of morphologic left ventricular dysfunction, sometimes associated with neoaortic valve regurgitation, and the minority of cases need aortic valve replacement. The long-term function of the morphologic left ventricle and the aortic valve need careful surveillance in the future. The atrial-Rastelli group of patients has not in the medium term shown evidence of ventricular dysfunction but will require change on a regular basis of their ventricular to pulmonary artery valved conduits.

Battery switch for downhole tools

Science.gov (United States)

Boling, Brian E.

2010-02-23

An electrical circuit for a downhole tool may include a battery, a load electrically connected to the battery, and at least one switch electrically connected in series with the battery and to the load. The at least one switch may be configured to close when a tool temperature exceeds a selected temperature.

Design and testing of a surface switch for the dynamic load current multiplier on the SPHINX microsecond LTD

International Nuclear Information System (INIS)

Maysonnave, T.; Bayol, F.; Demol, G.; Almeida, T. d'; Morell, A.; Lassalle, F.; Grunenwald, J.; Chuvatin, A.S.; Pecastaing, L.; De Ferron, A.S.

2013-01-01

SPHINX is a microsecond linear transformer driver located at Atomic Energy Commission (CEA) Gramat (France), which can deliver a current pulse of 6 MA within 800 ns in a Z-pinch load. Using the concept of the dynamic load current multiplier (DLCM), which was proposed by Chuvatin, we expect to increase the load current above 6 MA, while decreasing its rise time to ∼300 ns. The DLCM developed by the CEA Gramat and International Technologies for High Pulsed Power (ITHPP) is a compact system made up of concentric electrodes (auto-transformer), a dynamic flux extruder (cylindrical wire array), a vacuum convolute (eight post-hole rods), and a closing switch (compact vacuum surface switch). The latter is a key component of the system, which is used to prevent the current from flowing into the load until the inductance builds up due to the implosion of the wire array. This paper presents the design and testing of the DLCM surface switch, resulting from both electrostatic simulations and experiments on the SPHINX generator. These studies, carried out either with or without load (open circuit), were valuable for a first experimental evaluation of the DLCM scheme in a microsecond regime and provided detailed information on the surface switch behavior. (authors)

Blood and Books: Performing Code Switching

Directory of Open Access Journals (Sweden)

Jeff Friedman

2008-05-01

Full Text Available Code switching is a linguistic term that identifies ways individuals use communication modes and registers to negotiate difference in social relations. This essay suggests that arts-based inquiry, in the form of choreography and performance, provides a suitable and efficacious location within which both verbal and nonverbal channels of code switching can be investigated. Blood and Books, a case study of dance choreography within the context of post-colonial Maori performance in Aotearoa/New Zealand, is described and analyzed for its performance of code switching. The essay is framed by a discussion of how arts-based research within tertiary higher education requires careful negotiation in the form of code switching, as performed by the author's reflexive use of vernacular and formal registers in the essay. URN: urn:nbn:de:0114-fqs0802462

CONTROL OF BOUNCING IN RF MEMS SWITCHES USING DOUBLE ELECTRODE

KAUST Repository

Abdul Rahim, Farhan

2014-01-01

MEMS based mechanical switches are seen to be the likely replacements for CMOS based switches due to the several advantages that these mechanical switches have over CMOS switches. Mechanical switches can be used in systems under extreme conditions

Specific features of the switch-on gate current and different switch-on modes in silicon carbide thyristors

International Nuclear Information System (INIS)

Yurkov, S N; Mnatsakanov, T T; Levinshtein, M E; Cheng, L; Palmour, J W

2014-01-01

The specific features of the temperature and bias dependences of the switch-on gate current in SiC thyristors are examined analytically for two possible switching mechanisms. The so-called γ-mechanism, which is highly typical of the conventional Si thyristors, is characterized by very weak temperature and bias dependences. By contrast, the so-called α-mechanism, which is very characteristic of SiC thyristors, is highly sensitive to changes in temperature and bias. If the thyristor is switched on by the α-mechanism, the switch-on gate current density decreases very steeply with increasing temperature. As a result, the thyristor can lose its working capacity at elevated temperatures due to the instability against even very weak impacts. With decreasing the bias voltage U a , the gate switch-on current increases very steeply, which can make switching the thyristor on difficult. The unintentional shunting, which is apparently present in high-voltage SiC thyristors, causes the transition from the α- to the γ-mechanism at elevated temperatures and high biases. It can be supposed that introduction of a controllable technological shunting of the emitter–thin base junction allows stabilization of the temperature and bias parameters of SiC thyristors. The analytical results are confirmed by computer simulations performed in wide temperature and bias ranges for a 4H-SiC thyristor of the 18 kV class. (paper)

Bistable switching in dual-frequency liquid crystals

Energy Technology Data Exchange (ETDEWEB)

Palto, S. P., E-mail: palto@online.ru; Barnik, M I [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2006-06-15

Various bistable switching modes in nematic liquid crystals with frequency inversion of the sign of dielectric anisotropy are revealed and investigated. Switching between states with different helicoidal distributions of the director field of a liquid crystal, as well as between uniform and helicoidal states, is realized by dual-frequency waveforms of a driving voltage. A distinctive feature of the dual-frequency switching is that the uniform planar distribution of the director field may correspond to a thermodynamically equilibrium state, and the chirality of an LC is not a necessary condition for switching to a helicoidal state.

A high-switching-frequency flyback converter in resonant mode

NARCIS (Netherlands)

Li, Jianting; van Horck, Frank B.M.; Daniel, Bobby J.; Bergveld, Henk Jan

2017-01-01

The demand of miniaturization of power systems has accelerated the research on high-switching-frequency power converters. A flyback converter in resonant mode that features low switching losses, less transformer losses, and low switching noise at high switching frequency is investigated in this

A solid-state dielectric elastomer switch for soft logic

Energy Technology Data Exchange (ETDEWEB)

Chau, Nixon [Biomimetics Laboratory, Auckland Bioengineering Institute, The University of Auckland, Level 6, 70 Symonds Street, Auckland 1010 (New Zealand); Slipher, Geoffrey A., E-mail: geoffrey.a.slipher.civ@mail.mil; Mrozek, Randy A. [U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783 (United States); O' Brien, Benjamin M. [StretchSense, Ltd., 27 Walls Rd., Penrose, Auckland 1061 (New Zealand); Anderson, Iain A. [Biomimetics Laboratory, Auckland Bioengineering Institute, The University of Auckland, Level 6, 70 Symonds Street, Auckland 1010 (New Zealand); StretchSense, Ltd., 27 Walls Rd., Penrose, Auckland 1061 (New Zealand); Department of Engineering Science, School of Engineering, The University of Auckland, Level 3, 70 Symonds Street, Auckland 1010 (New Zealand)

2016-03-07

In this paper, we describe a stretchable solid-state electronic switching material that operates at high voltage potentials, as well as a switch material benchmarking technique that utilizes a modular dielectric elastomer (artificial muscle) ring oscillator. The solid-state switching material was integrated into our oscillator, which self-started after 16 s and performed 5 oscillations at a frequency of 1.05 Hz with 3.25 kV DC input. Our materials-by-design approach for the nickel filled polydimethylsiloxane based switch has resulted in significant improvements over previous carbon grease-based switches in four key areas, namely, sharpness of switching behavior upon applied stretch, magnitude of electrical resistance change, ease of manufacture, and production rate. Switch lifetime was demonstrated to be in the range of tens to hundreds of cycles with the current process. An interesting and potentially useful strain-based switching hysteresis behavior is also presented.

A solid-state dielectric elastomer switch for soft logic

International Nuclear Information System (INIS)

Chau, Nixon; Slipher, Geoffrey A.; Mrozek, Randy A.; O'Brien, Benjamin M.; Anderson, Iain A.

2016-01-01

In this paper, we describe a stretchable solid-state electronic switching material that operates at high voltage potentials, as well as a switch material benchmarking technique that utilizes a modular dielectric elastomer (artificial muscle) ring oscillator. The solid-state switching material was integrated into our oscillator, which self-started after 16 s and performed 5 oscillations at a frequency of 1.05 Hz with 3.25 kV DC input. Our materials-by-design approach for the nickel filled polydimethylsiloxane based switch has resulted in significant improvements over previous carbon grease-based switches in four key areas, namely, sharpness of switching behavior upon applied stretch, magnitude of electrical resistance change, ease of manufacture, and production rate. Switch lifetime was demonstrated to be in the range of tens to hundreds of cycles with the current process. An interesting and potentially useful strain-based switching hysteresis behavior is also presented.

Buck Converter with Soft-Switching Cells for PV Panel Applications

Directory of Open Access Journals (Sweden)

Cheng-Tao Tsai

2016-03-01

Full Text Available In power conversion of photovoltaic (PV energy, a hard-switching buck converter always generates some disadvantages. For example, serious electromagnetic interference (EMI, high switching losses, and stresses on an active switch (metal-oxide-semiconductor-field-effect-transistor, MOSFET, and high reverse-recovery losses of a freewheeling diode result in low conversion efficiency. To release these disadvantages, a buck converter with soft-switching cells for PV panel applications is proposed. To create zero-voltage-switching (ZVS features of the active switches, a simple active soft-switching cell with an inductor, a capacitor, and a MOSFET is incorporated into the proposed buck converter. Therefore, the switching losses and stresses of the active switches and EMI can be reduced significantly. To reduce reverse-recovery losses of a freewheeling diode, a simple passive soft-switching cell with a capacitor and two diodes is implemented. To verify the performance and the feasibility of the proposed buck converter with soft-switching cells for PV panel applications, a prototype soft-switching buck converter is built and implemented by using a maximum-power-point-tracking (MPPT method. Simulated and experimental results are presented from a 100 W soft-switching buck converter for PV panel applications.

High-power semiconductor RSD-based switch

Energy Technology Data Exchange (ETDEWEB)

Bezuglov, V G; Galakhov, I V; Grusin, I A [All-Russian Scientific Research Inst. of Experimental Physics, Sarov (Russian Federation); and others

1997-12-31

The operating principle and test results of a high-power semiconductor RSD-based switch with the following operating parameters is described: operating voltage 25 kV, peak operating current 200 kA, maximum transferred charge 70 C. The switch is intended for use by high-power capacitor banks of state-of-the-art research facilities. The switch was evaluated for applicability in commercial pulsed systems. The possibility of increasing the peak operating current to 500 kA is demonstrated. (author). 4 figs., 2 refs.

A novel multi-actuation CMOS RF MEMS switch

Science.gov (United States)

Lee, Chiung-I.; Ko, Chih-Hsiang; Huang, Tsun-Che

2008-12-01

This paper demonstrates a capacitive shunt type RF MEMS switch, which is actuated by electro-thermal actuator and electrostatic actuator at the same time, and than latching the switching status by electrostatic force only. Since thermal actuators need relative low voltage compare to electrostatic actuators, and electrostatic force needs almost no power to maintain the switching status, the benefits of the mechanism are very low actuation voltage and low power consumption. Moreover, the RF MEMS switch has considered issues for integrated circuit compatible in design phase. So the switch is fabricated by a standard 0.35um 2P4M CMOS process and uses wet etching and dry etching technologies for postprocess. This compatible ability is important because the RF characteristics are not only related to the device itself. If a packaged RF switch and a packaged IC wired together, the parasitic capacitance will cause the problem for optimization. The structure of the switch consists of a set of CPW transmission lines and a suspended membrane. The CPW lines and the membrane are in metal layers of CMOS process. Besides, the electro-thermal actuators are designed by polysilicon layer of the CMOS process. So the RF switch is only CMOS process layers needed for both electro-thermal and electrostatic actuations in switch. The thermal actuator is composed of a three-dimensional membrane and two heaters. The membrane is a stacked step structure including two metal layers in CMOS process, and heat is generated by poly silicon resistors near the anchors of membrane. Measured results show that the actuation voltage of the switch is under 7V for electro-thermal added electrostatic actuation.

Congenital blindness limits allocentric to egocentric switching ability.

Science.gov (United States)

Ruggiero, Gennaro; Ruotolo, Francesco; Iachini, Tina

2018-03-01

Many everyday spatial activities require the cooperation or switching between egocentric (subject-to-object) and allocentric (object-to-object) spatial representations. The literature on blind people has reported that the lack of vision (congenital blindness) may limit the capacity to represent allocentric spatial information. However, research has mainly focused on the selective involvement of egocentric or allocentric representations, not the switching between them. Here we investigated the effect of visual deprivation on the ability to switch between spatial frames of reference. To this aim, congenitally blind (long-term visual deprivation), blindfolded sighted (temporary visual deprivation) and sighted (full visual availability) participants were compared on the Ego-Allo switching task. This task assessed the capacity to verbally judge the relative distances between memorized stimuli in switching (from egocentric-to-allocentric: Ego-Allo; from allocentric-to-egocentric: Allo-Ego) and non-switching (only-egocentric: Ego-Ego; only-allocentric: Allo-Allo) conditions. Results showed a difficulty in congenitally blind participants when switching from allocentric to egocentric representations, not when the first anchor point was egocentric. In line with previous results, a deficit in processing allocentric representations in non-switching conditions also emerged. These findings suggest that the allocentric deficit in congenital blindness may determine a difficulty in simultaneously maintaining and combining different spatial representations. This deficit alters the capacity to switch between reference frames specifically when the first anchor point is external and not body-centered.

CONTROL OF BOUNCING IN RF MEMS SWITCHES USING DOUBLE ELECTRODE

KAUST Repository