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Sample records for n-qubit toffoli gate

  1. Decompositions of n-qubit Toffoli Gates with Linear Circuit Complexity

    NASA Astrophysics Data System (ADS)

    He, Yong; Luo, Ming-Xing; Zhang, E.; Wang, Hong-Ke; Wang, Xiao-Feng

    2017-07-01

    Toffoli gates are natural elements for the circuit model based quantum computation. We investigate general resource requirements for arbitrary n-qubit Toffoli gate. These resources consist of the nontrivial Clifford gate (CNOT), non-Clifford gate ( T gate), ancillary qubits, and circuit depth. To implement n-qubit Toffoli gates, we consider two cases: only one auxiliary qubit and unlimited auxiliary qubits. The key of the first case is to decompose an n-qubit Toffoli gate into the reduced Toffoli gate modulo phase shift using the Clifford gates and one ancillary qubit. With this construction, it only requires O( n) number of general resources for an n-qubit Toffoli gate. For the second case, an approximate Toffoli gate is constructed to obtain efficient decomposition of a Toffoli gate. The new decomposition can further reduce general resources except auxiliary qubits.

  2. Deterministic linear optical quantum Toffoli gate

    NASA Astrophysics Data System (ADS)

    Huang, He-Liang; Bao, Wan-Su; Li, Tan; Li, Feng-Guang; Fu, Xiang-Qun; Zhang, Shuo; Zhang, Hai-Long; Wang, Xiang

    2017-09-01

    Quantum Toffoli gate is a crucial part of many quantum information processing schemes. We design a deterministic linear optical quantum Toffoli gate using three degrees of freedom of a single photon. The proposed setup does not require any ancilla photons and is experimentally feasible with current technology. Moreover, we show that our setup can be directly used to demonstrate that hypergraph states violate local realism in an extreme manner.

  3. Hybrid Toffoli gate on photons and quantum spins

    PubMed Central

    Luo, Ming-Xing; Ma, Song-Ya; Chen, Xiu-Bo; Wang, Xiaojun

    2015-01-01

    Quantum computation offers potential advantages in solving a number of interesting and difficult problems. Several controlled logic gates, the elemental building blocks of quantum computer, have been realized with various physical systems. A general technique was recently proposed that significantly reduces the realization complexity of multiple-control logic gates by harnessing multi-level information carriers. We present implementations of a key quantum circuit: the three-qubit Toffoli gate. By exploring the optical selection rules of one-sided optical microcavities, a Toffoli gate may be realized on all combinations of photon and quantum spins in the QD-cavity. The three general controlled-NOT gates are involved using an auxiliary photon with two degrees of freedom. Our results show that photons and quantum spins may be used alternatively in quantum information processing. PMID:26568078

  4. High-Fidelity Single-Shot Toffoli Gate via Quantum Control.

    PubMed

    Zahedinejad, Ehsan; Ghosh, Joydip; Sanders, Barry C

    2015-05-22

    A single-shot Toffoli, or controlled-controlled-not, gate is desirable for classical and quantum information processing. The Toffoli gate alone is universal for reversible computing and, accompanied by the Hadamard gate, forms a universal gate set for quantum computing. The Toffoli gate is also a key ingredient for (nontopological) quantum error correction. Currently Toffoli gates are achieved by decomposing into sequentially implemented single- and two-qubit gates, which require much longer times and yields lower overall fidelities compared to a single-shot implementation. We develop a quantum-control procedure to construct a single-shot Toffoli gate for three nearest-neighbor-coupled superconducting transmon systems such that the fidelity is 99.9% and is as fast as an entangling two-qubit gate under the same realistic conditions. The gate is achieved by a nongreedy quantum control procedure using our enhanced version of the differential evolution algorithm.

  5. Tomographic characterization of a linear optical quantum Toffoli gate

    NASA Astrophysics Data System (ADS)

    Mičuda, M.; Miková, M.; Straka, I.; Sedlák, M.; Dušek, M.; Ježek, M.; Fiurášek, J.

    2015-09-01

    We report on a detailed characterization of a three-qubit linear optical quantum Toffoli gate. Our experiment utilizes correlated photon pairs generated in the process of spontaneous parametric down-conversion. Two qubits are encoded into polarization and spatial degrees of freedom of a signal photon, and the third qubit is represented by polarization of an idler photon. The linear optical Toffoli gate is implemented by interference of photons on a partially polarizing beam splitter inserted inside a Mach Zehnder interferometer formed by two calcite beam displacers. We have measured 4032 different two-photon coincidences, which allows us to estimate the fidelity of the gate to be 90%. Although these data are not tomographically complete, we show that they are sufficient for a reliable reconstruction of the quantum process matrix of the gate via the recently proposed maximum likelihood-maximum entropy estimation procedure. To probe the entangling capability of the gate, we have investigated generation of three-qubit GHZ states from fully and partially separable input states and we have performed a full tomography of the output states. We compare the reconstructed states with theoretical predictions obtained with the use of the estimated quantum process matrix and obtain a very good agreement.

  6. Multifractality in fidelity sequences of optimized Toffoli gates

    NASA Astrophysics Data System (ADS)

    Moqadam, Jalil Khatibi; Welter, Guilherme S.; Esquef, Paulo A. A.

    2016-11-01

    We analyze the multifractality in the fidelity sequences of several engineered Toffoli gates. Using quantum control methods, we consider several optimization problems whose global solutions realize the gate in a chain of three qubits with XY Heisenberg interaction. Applying a minimum number of control pulses assuring a fidelity above 99 % in the ideal case, we design stable gates that are less sensitive to variations in the interqubits couplings. The most stable gate has the fidelity above 91 % with variations about 0.1 %, for up to 10 % variation in the nominal couplings. We perturb the system by introducing a single source of 1 / f noise that affects all the couplings. In order to quantify the performance of the proposed optimized gates, we calculate the fidelity of a large set of optimized gates under prescribed levels of coupling perturbation. Then, we run multifractal analysis on the sequence of attained fidelities. This way, gate performance can be assessed beyond mere average results, since the chosen multifractality measure (the width of the multifractal spectrum) encapsulates into a single performance indicator the spread of fidelity values around the mean and the presence of outliers. The higher the value of the performance indicator the more concentrated around the mean the fidelity values are and rarer is the occurrence of outliers. The results of the multifractal analysis on the fidelity sequences demonstrate the effectiveness of the proposed optimized gate implementations, in the sense they are rendered less sensitive to variations in the interqubits coupling strengths.

  7. Demonstrating the possibility of implementing the Toffoli gate in crystals doped by rare-earth metal ions

    NASA Astrophysics Data System (ADS)

    Akhmedzhanov, R. A.; Gushchin, L. A.; Zelensky, I. V.; Malakyan, Yu. P.; Sobgaida, D. A.

    2015-07-01

    A scheme for the implementation of the Toffoli gate in inorganic crystals doped by rare-earth metal ions is proposed. A numerical analysis of the factors affecting the fidelity of the Toffoli gate implementation is carried out, and estimates for the available experimental parameters are obtained. A demonstration experiment is set up in which behavior similar to the Toffoli gate is shown for ensembles of Pr3+ ions doped into a LaF3 crystal.

  8. Quantum gate learning in qubit networks: Toffoli gate without time-dependent control

    NASA Astrophysics Data System (ADS)

    Banchi, Leonardo; Pancotti, Nicola; Bose, Sougato

    2016-07-01

    We put forward a strategy to encode a quantum operation into the unmodulated dynamics of a quantum network without the need for external control pulses, measurements or active feedback. Our optimisation scheme, inspired by supervised machine learning, consists in engineering the pairwise couplings between the network qubits so that the target quantum operation is encoded in the natural reduced dynamics of a network section. The efficacy of the proposed scheme is demonstrated by the finding of uncontrolled four-qubit networks that implement either the Toffoli gate, the Fredkin gate or remote logic operations. The proposed Toffoli gate is stable against imperfections, has a high fidelity for fault-tolerant quantum computation and is fast, being based on the non-equilibrium dynamics.

  9. n-qubit-controlled phase gate with superconducting quantum-interference devices coupled to a resonator

    SciTech Connect

    Yang Chuiping; Han Siyuan

    2005-09-15

    We present a way to realize an n-qubit controlled phase gate with superconducting quantum-interference devices (SQUIDs) by coupling them to a superconducting resonator. In this proposal, the two logical states of a qubit are represented by the two lowest levels of a SQUID. An intermediate level of each SQUID is utilized to facilitate coherent control and manipulation of quantum states of the qubits. It is interesting to note that an n-qubit controlled phase gate can be achieved with n SQUIDs by successively applying a {pi}/2 Jaynes-Cummings pulse to each of the n-1 control SQUIDs before and after a {pi} Jaynes-Cummings pulse on the target SQUID.

  10. Simple trapped-ion architecture for high-fidelity Toffoli gates

    SciTech Connect

    Borrelli, Massimo; Paternostro, Mauro; Maniscalco, Sabrina

    2011-07-15

    We discuss a simple architecture for a quantum toffoli gate implemented using three trapped ions. The gate, which, in principle, can be implemented with a single laser-induced operation, is effective under rather general conditions and is strikingly robust (within any experimentally realistic range of values) against dephasing, heating, and random fluctuations of the Hamiltonian parameters. We provide a full characterization of the unitary and noise-affected gate using three-qubit quantum process tomography.

  11. Logic reversibility and thermodynamic irreversibility demonstrated by DNAzyme-based Toffoli and Fredkin logic gates.

    PubMed

    Orbach, Ron; Remacle, Françoise; Levine, R D; Willner, Itamar

    2012-12-26

    The Toffoli and Fredkin gates were suggested as a means to exhibit logic reversibility and thereby reduce energy dissipation associated with logic operations in dense computing circuits. We present a construction of the logically reversible Toffoli and Fredkin gates by implementing a library of predesigned Mg(2+)-dependent DNAzymes and their respective substrates. Although the logical reversibility, for which each set of inputs uniquely correlates to a set of outputs, is demonstrated, the systems manifest thermodynamic irreversibility originating from two quite distinct and nonrelated phenomena. (i) The physical readout of the gates is by fluorescence that depletes the population of the final state of the machine. This irreversible, heat-releasing process is needed for the generation of the output. (ii) The DNAzyme-powered logic gates are made to operate at a finite rate by invoking downhill energy-releasing processes. Even though the three bits of Toffoli's and Fredkin's logically reversible gates manifest thermodynamic irreversibility, we suggest that these gates could have important practical implication in future nanomedicine.

  12. Realization of an n-qubit controlled-U gate with superconducting quantum interference devices or atoms in cavity QED

    SciTech Connect

    Yang Chuiping; Han Siyuan

    2006-03-15

    We propose an approach to realize an n-qubit controlled-U gate with superconducting quantum interference devices (SQUIDs) in cavity QED. In this approach, the two lowest levels of a SQUID represent the two logical states of a qubit while a higher-energy intermediate level serves the gate manipulation. Our method operates essentially by creating a single photon through one of the control SQUIDs and then performing an arbitrary unitary transformation on the target SQUID with the assistance of the cavity photon. In addition, we show that the method can be applied to implement an n-qubit controlled-U gate with atomic qubits in cavity QED.

  13. Fredkin and Toffoli Gates Implemented in Oregonator Model of Belousov-Zhabotinsky Medium

    NASA Astrophysics Data System (ADS)

    Adamatzky, Andrew

    A thin-layer Belousov-Zhabotinsky (BZ) medium is a powerful computing device capable for implementing logical circuits, memory, image processors, robot controllers, and neuromorphic architectures. We design the reversible logical gates — Fredkin gate and Toffoli gate — in a BZ medium network of excitable channels with subexcitable junctions. Local control of the BZ medium excitability is an important feature of the gates’ design. An excitable thin-layer BZ medium responds to a localized perturbation with omnidirectional target or spiral excitation waves. A subexcitable BZ medium responds to an asymmetric perturbation by producing traveling localized excitation wave-fragments similar to dissipative solitons. We employ interactions between excitation wave-fragments to perform the computation. We interpret the wave-fragments as values of Boolean variables. The presence of a wave-fragment at a given site of a circuit represents the logical truth, absence of the wave-fragment — logically false. Fredkin gate consists of ten excitable channels intersecting at 11 junctions, eight of which are subexcitable. Toffoli gate consists of six excitable channels intersecting at six junctions, four of which are subexcitable. The designs of the gates are verified using numerical integration of two-variable Oregonator equations.

  14. Logic reversibility and thermodynamic irreversibility demonstrated by DNAzyme-based Toffoli and Fredkin logic gates

    PubMed Central

    Orbach, Ron; Remacle, Françoise; Levine, R. D.; Willner, Itamar

    2012-01-01

    The Toffoli and Fredkin gates were suggested as a means to exhibit logic reversibility and thereby reduce energy dissipation associated with logic operations in dense computing circuits. We present a construction of the logically reversible Toffoli and Fredkin gates by implementing a library of predesigned Mg2+-dependent DNAzymes and their respective substrates. Although the logical reversibility, for which each set of inputs uniquely correlates to a set of outputs, is demonstrated, the systems manifest thermodynamic irreversibility originating from two quite distinct and nonrelated phenomena. (i) The physical readout of the gates is by fluorescence that depletes the population of the final state of the machine. This irreversible, heat-releasing process is needed for the generation of the output. (ii) The DNAzyme-powered logic gates are made to operate at a finite rate by invoking downhill energy-releasing processes. Even though the three bits of Toffoli’s and Fredkin’s logically reversible gates manifest thermodynamic irreversibility, we suggest that these gates could have important practical implication in future nanomedicine. PMID:23236131

  15. Alternative approach of developing all-optical Fredkin and Toffoli gates

    NASA Astrophysics Data System (ADS)

    Mandal, Dhoumendra; Mandal, Sumana; Garai, Sisir Kumar

    2015-09-01

    Reversible logic gates show potential roles in communication technology, and it has a wide area of applicability such as in sequential and combinational circuit of optical computing, optical signal processing, multi-valued logic operations, etc. because of its advantageous aspects of data-recovering capabilities, low power consumption, least power dissipation, faster speed of processing, less hardware complexity, etc. In a reversible logic gate not only the outputs can be determined from the inputs, but also the inputs can be uniquely recovered from the outputs. In this article an alternative approach has been made to develop three-input-output Fredkin and Toffoli gates using the frequency conversion property of semiconductor optical amplifier (SOA) and frequency-based beam routing by optical multiplexers and demultiplexers. Simulation results show the feasibility of our proposed scheme.

  16. Realization of an ultrafast all-optical Toffoli logic gate based on the phase relation between two second order nonlinear optical signals

    NASA Astrophysics Data System (ADS)

    Kazemi, Mehdi Mohammad; Mazaheri Tehrani, Alireza; Zeb Khan, Tahir; Namboodiri, Mahesh; Materny, Arnulf

    2015-12-01

    A Toffoli logic gate (CCNOT gate) is a universal reversible logic gate from which all other reversible gates can be constructed. It has a three-bit input and output. The goal of our work was to realize a Toffoli gate where all inputs and outputs are realized optically, which allows for ultrafast switching processes. We demonstrate experimentally that a Toffoli logic gate can be created based on nonlinear multi-wave interactions of light with matter. Using femtosecond laser pulses, the all-optical Toffoli gate is based on the coherence of the optical signals produced via the nonlinear optical processes. Sum frequency (SF) and second harmonic (SH) generations are combined in such a way so as to yield the complete truth table of the universal reversible logic gate.

  17. Implementations of two-photon four-qubit Toffoli and Fredkin gates assisted by nitrogen-vacancy centers.

    PubMed

    Wei, Hai-Rui; Zhu, Pei-Jin

    2016-10-24

    It is desirable to implement an efficient quantum information process demanding fewer quantum resources. We designed two compact quantum circuits for determinately implementing four-qubit Toffoli and Fredkin gates on single-photon systems in both the polarization and spatial degrees of freedom (DoFs) via diamond nitrogen-vacancy (NV) centers in resonators. The gates are heralded by the electron spins associated with the diamond NV centers. In contrast to the ones with one DoF, our implementations reduce the quantum resource and are robust against the decoherence. Evaluations of fidelities and efficiencies of our gates show that our schemes may be implemented with current technology.

  18. Implementations of two-photon four-qubit Toffoli and Fredkin gates assisted by nitrogen-vacancy centers

    NASA Astrophysics Data System (ADS)

    Wei, Hai-Rui; Zhu, Pei-Jin

    2016-10-01

    It is desirable to implement an efficient quantum information process demanding fewer quantum resources. We designed two compact quantum circuits for determinately implementing four-qubit Toffoli and Fredkin gates on single-photon systems in both the polarization and spatial degrees of freedom (DoFs) via diamond nitrogen-vacancy (NV) centers in resonators. The gates are heralded by the electron spins associated with the diamond NV centers. In contrast to the ones with one DoF, our implementations reduce the quantum resource and are robust against the decoherence. Evaluations of fidelities and efficiencies of our gates show that our schemes may be implemented with current technology.

  19. Implementations of two-photon four-qubit Toffoli and Fredkin gates assisted by nitrogen-vacancy centers

    PubMed Central

    Wei, Hai-Rui; Zhu, Pei-Jin

    2016-01-01

    It is desirable to implement an efficient quantum information process demanding fewer quantum resources. We designed two compact quantum circuits for determinately implementing four-qubit Toffoli and Fredkin gates on single-photon systems in both the polarization and spatial degrees of freedom (DoFs) via diamond nitrogen-vacancy (NV) centers in resonators. The gates are heralded by the electron spins associated with the diamond NV centers. In contrast to the ones with one DoF, our implementations reduce the quantum resource and are robust against the decoherence. Evaluations of fidelities and efficiencies of our gates show that our schemes may be implemented with current technology. PMID:27774994

  20. Simulation of n-qubit quantum systems. I. Quantum registers and quantum gates

    NASA Astrophysics Data System (ADS)

    Radtke, T.; Fritzsche, S.

    2005-12-01

    During recent years, quantum computations and the study of n-qubit quantum systems have attracted a lot of interest, both in theory and experiment. Apart from the promise of performing quantum computations, however, these investigations also revealed a great deal of difficulties which still need to be solved in practice. In quantum computing, unitary and non-unitary quantum operations act on a given set of qubits to form (entangled) states, in which the information is encoded by the overall system often referred to as quantum registers. To facilitate the simulation of such n-qubit quantum systems, we present the FEYNMAN program to provide all necessary tools in order to define and to deal with quantum registers and quantum operations. Although the present version of the program is restricted to unitary transformations, it equally supports—whenever possible—the representation of the quantum registers both, in terms of their state vectors and density matrices. In addition to the composition of two or more quantum registers, moreover, the program also supports their decomposition into various parts by applying the partial trace operation and the concept of the reduced density matrix. Using an interactive design within the framework of MAPLE, therefore, we expect the FEYNMAN program to be helpful not only for teaching the basic elements of quantum computing but also for studying their physical realization in the future. Program summaryTitle of program:FEYNMAN Catalogue number:ADWE Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADWE Program obtainable from:CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions:None Computers for which the program is designed:All computers with a license of the computer algebra system MAPLE [Maple is a registered trademark of Waterlo Maple Inc.] Operating systems or monitors under which the program has been tested:Linux, MS Windows XP Programming language used:MAPLE 9.5 (but should be compatible

  1. Teleportation of a Toffoli gate among distant solid-state qubits with quantum dots embedded in optical microcavities.

    PubMed

    Hu, Shi; Cui, Wen-Xue; Wang, Dong-Yang; Bai, Cheng-Hua; Guo, Qi; Wang, Hong-Fu; Zhu, Ai-Dong; Zhang, Shou

    2015-07-30

    Teleportation of unitary operations can be viewed as a quantum remote control. The remote realization of robust multiqubit logic gates among distant long-lived qubit registers is a key challenge for quantum computation and quantum information processing. Here we propose a simple and deterministic scheme for teleportation of a Toffoli gate among three spatially separated electron spin qubits in optical microcavities by using local linear optical operations, an auxiliary electron spin, two circularly-polarized entangled photon pairs, photon measurements, and classical communication. We assess the feasibility of the scheme and show that the scheme can be achieved with high average fidelity under the current technology. The scheme opens promising perspectives for constructing long-distance quantum communication and quantum computation networks with solid-state qubits.

  2. A proposal for implementing an n-qubit controlled-rotation gate with three-level superconducting qubit systems in cavity QED.

    PubMed

    Yang, Chui-Ping

    2011-06-08

    We present a method for implementing an n-qubit controlled-rotation gate with three-level superconducting qubit systems in cavity quantum electrodynamics. The two logical states of a qubit are represented by the two lowest levels of each system while a higher energy level is used for the gate implementation. The method operates essentially by preparing a W state conditioned on the states of the control qubits, creating a single photon in the cavity mode, and then performing an arbitrary rotation on the states of the target qubit with the assistance of the cavity photon. It is interesting to note that the basic operational steps for implementing the proposed gate do not increase with the number of qubits n, and the gate operation time decreases as the number of qubits increases. This proposal is quite general, and can be applied to various types of superconducting devices in a cavity or coupled to a resonator.

  3. Implementation of a nonlocal N-qubit conditional phase gate using the nitrogen-vacancy center and microtoroidal resonator coupled systems

    NASA Astrophysics Data System (ADS)

    Cao, Cong; Liu, Gang; Zhang, Ru; Wang, Chuan

    2014-04-01

    Implementation of a nonlocal multi-qubit conditional phase gate is an essential requirement in some quantum information processing (QIP) tasks. Recently, a novel solid-state cavity quantum electrodynamics (QED) system, in which the nitrogen-vacancy (NV) center in diamond is coupled to a microtoroidal resonator (MTR), has been proposed as a potential system for hybrid quantum information and computing. By virtue of such systems, we present a scheme to realize a nonlocal N-qubit conditional phase gate directly. Our scheme employs a cavity input-output process and single-photon interference, without the use of any auxiliary entanglement pair or classical communication. Considering the currently available technologies, our scheme might be quite useful among different nodes in quantum networks for large-scaled QIP.

  4. All-optical four-bit Toffoli gate with possible implementation in solids

    NASA Astrophysics Data System (ADS)

    Grigoryan, G.; Chaltykyan, V.; Gazazyan, E.; Tikhova, O.

    2013-05-01

    We examine in detail the cyclic adiabatic population transfer methods for five-level diagrams in order to construct a four-bit universal reversible logic gate. We show that under certain conditions and sequence of turning on and off the laser pulses a five-level system may be reduced to an effective Λ-diagram.

  5. Efficient three-qubit entangling (Toffoli) gates via excited states in qubit-cavity systems.

    NASA Astrophysics Data System (ADS)

    Reinecke, Thomas; Economou, Sophia; Solenov, Dmitry

    2014-03-01

    Efficient multi-qubit quantum operations are crucial for further development of quantum information processing using available physical designs. We report our results on efficient three-qubit entangling operations in qubit-cavity systems. The proposed gate design is based on non-commutativity of single-qubit pulse controls that can be achieved for systems in which auxiliary states above the qubit subspace are available. It does not rely on dynamical tuning of energy states, and, unlike traditional decomposition approaches, it provides efficiency comparable to that of a single control-NOT operation. We will focus on the transmon qubit systems, which have recently demonstrated coherence times suitable for multi-qubit computation. Other systems will also be discussed.

  6. Simulation of n-qubit quantum systems. V. Quantum measurements

    NASA Astrophysics Data System (ADS)

    Radtke, T.; Fritzsche, S.

    2010-02-01

    The FEYNMAN program has been developed during the last years to support case studies on the dynamics and entanglement of n-qubit quantum registers. Apart from basic transformations and (gate) operations, it currently supports a good number of separability criteria and entanglement measures, quantum channels as well as the parametrizations of various frequently applied objects in quantum information theory, such as (pure and mixed) quantum states, hermitian and unitary matrices or classical probability distributions. With the present update of the FEYNMAN program, we provide a simple access to (the simulation of) quantum measurements. This includes not only the widely-applied projective measurements upon the eigenspaces of some given operator but also single-qubit measurements in various pre- and user-defined bases as well as the support for two-qubit Bell measurements. In addition, we help perform generalized and POVM measurements. Knowing the importance of measurements for many quantum information protocols, e.g., one-way computing, we hope that this update makes the FEYNMAN code an attractive and versatile tool for both, research and education. New version program summaryProgram title: FEYNMAN Catalogue identifier: ADWE_v5_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADWE_v5_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 27 210 No. of bytes in distributed program, including test data, etc.: 1 960 471 Distribution format: tar.gz Programming language: Maple 12 Computer: Any computer with Maple software installed Operating system: Any system that supports Maple; the program has been tested under Microsoft Windows XP and Linux Classification: 4.15 Catalogue identifier of previous version: ADWE_v4_0 Journal reference of previous version: Comput. Phys. Commun

  7. Simulation of n-qubit quantum systems. III. Quantum operations

    NASA Astrophysics Data System (ADS)

    Radtke, T.; Fritzsche, S.

    2007-05-01

    often result in very large symbolic expressions that dramatically slow down the evaluation of measures or other quantities. In these cases, MAPLE's assume facility sometimes helps to reduce the complexity of symbolic expressions, but often only numerical evaluation is possible. Since the complexity of the FEYNMAN commands is very different, no general scaling law for the CPU time and memory usage can be given. No. of bytes in distributed program including test data, etc.: 799 265 No. of lines in distributed program including test data, etc.: 18 589 Distribution format: tar.gz Reasons for new version: While the previous program versions were designed mainly to create and manipulate the state of quantum registers, the present extension aims to support quantum operations as the essential ingredient for studying the effects of noisy environments. Does this version supersede the previous version: Yes Nature of the physical problem: Today, entanglement is identified as the essential resource in virtually all aspects of quantum information theory. In most practical implementations of quantum information protocols, however, decoherence typically limits the lifetime of entanglement. It is therefore necessary and highly desirable to understand the evolution of entanglement in noisy environments. Method of solution: Using the computer algebra system MAPLE, we have developed a set of procedures that support the definition and manipulation of n-qubit quantum registers as well as (unitary) logic gates and (nonunitary) quantum operations that act on the quantum registers. The provided hierarchy of commands can be used interactively in order to simulate and analyze the evolution of n-qubit quantum systems in ideal and nonideal quantum circuits.

  8. Generalized monogamy relations of concurrence for N -qubit systems

    NASA Astrophysics Data System (ADS)

    Zhu, Xue-Na; Fei, Shao-Ming

    2015-12-01

    We present a different kind of monogamous relations based on concurrence and concurrence of assistance. For N -qubit systems A B C1...CN -2 , the monogamy relations satisfied by the concurrence of N -qubit pure states under the partition A B and C1...CN -2 , as well as under the partition A B C1 and C2...CN -2 , are established, which gives rise to a kind of restrictions on the entanglement distribution and trade off among the subsystems.

  9. Geometric multiaxial representation of N -qubit mixed symmetric separable states

    NASA Astrophysics Data System (ADS)

    SP, Suma; Sirsi, Swarnamala; Hegde, Subramanya; Bharath, Karthik

    2017-08-01

    The study of N -qubit mixed symmetric separable states is a longstanding challenging problem as no unique separability criterion exists. In this regard, we take up the N -qubit mixed symmetric separable states for a detailed study as these states are of experimental importance and offer an elegant mathematical analysis since the dimension of the Hilbert space is reduced from 2N to N +1 . Since there exists a one-to-one correspondence between the spin-j system and an N -qubit symmetric state, we employ Fano statistical tensor parameters for the parametrization of the spin-density matrix. Further, we use a geometric multiaxial representation (MAR) of the density matrix to characterize the mixed symmetric separable states. Since the separability problem is NP-hard, we choose to study it in the continuum limit where mixed symmetric separable states are characterized by the P -distribution function λ (θ ,ϕ ) . We show that the N -qubit mixed symmetric separable states can be visualized as a uniaxial system if the distribution function is independent of θ and ϕ . We further choose a distribution function to be the most general positive function on a sphere and observe that the statistical tensor parameters characterizing the N -qubit symmetric system are the expansion coefficients of the distribution function. As an example for the discrete case, we investigate the MAR of a uniformly weighted two-qubit mixed symmetric separable state. We also observe that there exists a correspondence between the separability and classicality of states.

  10. Reversible circuit synthesis by genetic programming using dynamic gate libraries

    NASA Astrophysics Data System (ADS)

    Abubakar, Mustapha Y.; Jung, Low Tang; Zakaria, Nordin; Younes, Ahmed; Abdel-Aty, Abdel-Haleem

    2017-06-01

    We have defined a new method for automatic construction of reversible logic circuits by using the genetic programming approach. The choice of the gate library is 100% dynamic. The algorithm is capable of accepting all possible combinations of the following gate types: NOT TOFFOLI, NOT PERES, NOT CNOT TOFFOLI, NOT CNOT SWAP FREDKIN, NOT CNOT TOFFOLI SWAP FREDKIN, NOT CNOT PERES, NOT CNOT SWAP FREDKIN PERES, NOT CNOT TOFFOLI PERES and NOT CNOT TOFFOLI SWAP FREDKIN PERES. Our method produced near optimum circuits in some cases when a particular subset of gate types was used in the library. Meanwhile, in some cases, optimal circuits were produced due to the heuristic nature of the algorithm. We compared the outcomes of our method with several existing synthesis methods, and it was shown that our algorithm performed relatively well compared to the previous synthesis methods in terms of the output efficiency of the algorithm and execution time as well.

  11. Entanglement equivalence of N-qubit symmetric states

    SciTech Connect

    Mathonet, P.; Krins, S.; Bastin, T.; Godefroid, M.; Solano, E.

    2010-05-15

    We study the interconversion of multipartite symmetric N-qubit states under stochastic local operations and classical communication (SLOCC). We demonstrate that if two symmetric states can be connected with a nonsymmetric invertible local operation (ILO), then they belong necessarily to the separable, W, or Greenberger-Horne-Zeilinger (GHZ) entanglement class, establishing a practical method of discriminating subsets of entanglement classes. Furthermore, we prove that there always exists a symmetric ILO connecting any pair of symmetric N-qubit states equivalent under SLOCC, simplifying the requirements for experimental implementations of local interconversion of those states.

  12. Simulation of n-qubit quantum systems. II. Separability and entanglement

    NASA Astrophysics Data System (ADS)

    Radtke, T.; Fritzsche, S.

    2006-07-01

    increase of the associated Hilbert space. No. of lines in distributed program, including test data, etc.:3107 No. of bytes in distributed program, including test data, etc.:13 859 Distribution format:tar.gz Reasons for new version:The first program version established the data structures and commands which are needed to build and manipulate quantum registers. Since the (evolution of) entanglement is a central aspect in quantum information processing the current version adds the capability to analyze separability and entanglement of quantum registers by implementing algebraic separability criteria and entanglement measures and related quantities. Does this version supersede the previous version: Yes Nature of the physical problem: Entanglement has been identified as an essential resource in virtually all aspects of quantum information theory. Therefore, the detection and quantification of entanglement is a necessary prerequisite for many applications, such as quantum computation, communications or quantum cryptography. Up to the present, however, the multipartite entanglement of n-qubit systems has remained largely unexplored owing to the exponential growth of complexity with the number of qubits involved. Method of solution: Using the computer algebra system MAPLE, a set of procedures has been developed which supports the definition and manipulation of n-qubit quantum registers and quantum logic gates [T. Radtke, S. Fritzsche, Comput. Phys. Comm. 173 (2005) 91]. The provided hierarchy of commands can be used interactively in order to simulate the behavior of n-qubit quantum systems (by applying a number of unitary or non-unitary operations) and to analyze their separability and entanglement properties. Restrictions onto the complexity of the problem: The present version of the program facilitates the setup and the manipulation of quantum registers by means of (predefined) quantum logic gates; it now also provides the tools for performing a symbolic and/or numeric analysis

  13. Decay of N-qubit GHZ states in Pauli channels

    NASA Astrophysics Data System (ADS)

    Chen, Xiao-Yu; Wang, Ting-Ting

    2015-08-01

    An N-qubit Greenberger-Horne-Zeilinger (GHZ) state has many applications in various quantum information tasks and can be realized in different experimental schemes. A GHZ diagonal state evolves to another GHZ diagonal state in independent parallel Pauli channels. We give the explicit expression of the resultant GHZ diagonal state in terms of the initial state and channel parameters. If the initial state is a pure N qubit GHZ state or a three-qubit GHZ diagonal state admits a condition, the full separability criterion of the Pauli noisy state is equivalent to positive partial transpose (PPT) criterion. Thus the fully separable condition follows. Project supported by the National Natural Science Foundation of China (Grant No. 11375152).

  14. Bounding the entanglement of N qubits with only four measurements

    NASA Astrophysics Data System (ADS)

    Hashemi Rafsanjani, S. M.; Broadbent, C. J.; Eberly, J. H.

    2013-12-01

    We introduce a measure for the genuinely N-partite (all-party) entanglement of N-qubit states using the trace distance metric and find an algebraic formula for the Greenberger-Horne-Zeilinger (GHZ)-diagonal states. We then use this formula to show how the all-party entanglement of experimentally produced GHZ states of an arbitrary number of qubits may be bounded with only four measurements.

  15. Local unitary invariants for N-qubit pure states

    SciTech Connect

    Sharma, S. Shelly; Sharma, N. K.

    2010-11-15

    The concept of negativity font, a basic unit of multipartite entanglement, is introduced. Transformation properties of determinants of negativity fonts under local unitary (LU) transformations are exploited to obtain relevant N-qubit polynomial invariants and construct entanglement monotones from first principles. It is shown that entanglement monotones that detect the entanglement of specific parts of the composite system may be constructed to distinguish between states with distinct types of entanglement. The structural difference between entanglement monotones for an odd and even number of qubits is brought out.

  16. Multibit gates for quantum computing.

    PubMed

    Wang, X; Sørensen, A; Mølmer, K

    2001-04-23

    We present a general technique to implement products of many qubit operators communicating via a joint harmonic oscillator degree of freedom in a quantum computer. By conditional displacements and rotations we can implement Hamiltonians which are trigonometric functions of qubit operators. With such operators we can effectively implement higher order gates such as Toffoli gates and C(n)-NOT gates, and we show that the entire Grover search algorithm can be implemented in a direct way.

  17. Entanglement and nonlocality in diagonal symmetric states of N qubits

    NASA Astrophysics Data System (ADS)

    Quesada, Ruben; Rana, Swapan; Sanpera, Anna

    2017-04-01

    We analyze entanglement and nonlocal properties of the convex set of symmetric N -qubit states which are diagonal in the Dicke basis. First, we demonstrate that within this set, semidefinite positivity of partial transposition (PPT) is necessary and sufficient for separability—which has also been reported recently by Yu [Phys. Rev. A 94, 060101(R) (2016), 10.1103/PhysRevA.94.060101]. Furthermore, we show which states among the entangled diagonal symmetric are nonlocal under two-body Bell inequalities. The diagonal symmetric convex set contains a simple and extended family of states that violate the weak Peres conjecture, being PPT with respect to one partition but violating a Bell inequality in such partition. Our method opens directions to address entanglement and nonlocality on higher dimensional symmetric states, where presently very few results are available.

  18. Recurrent construction of optimal entanglement witnesses for 2N-qubit systems

    NASA Astrophysics Data System (ADS)

    Zwolak, Justyna P.; Chruściński, Dariusz

    2014-05-01

    We provide a recurrent construction of entanglement witnesses for a bipartite systems living in a Hilbert space corresponding to 2N qubits (N qubits in each subsystem). Our construction provides a method of generalization of the Robertson map that naturally meshes with 2N-qubit systems, i.e., its structure respects the 22N growth of the state space. We prove that for N >1 these witnesses are indecomposable and optimal. As a byproduct we provide a family of PPT (Positive Partial Transpose) entangled states.

  19. Genuinely multipartite concurrence of N-qubit X matrices

    NASA Astrophysics Data System (ADS)

    Hashemi Rafsanjani, S. M.; Huber, M.; Broadbent, C. J.; Eberly, J. H.

    2012-12-01

    We find an algebraic formula for the N-partite concurrence of N qubits in an X matrix. X matrices are density matrices whose only nonzero elements are diagonal or antidiagonal when written in an orthonormal basis. We use our formula to study the dynamics of the N-partite entanglement of N remote qubits in generalized N-party Greenberger-Horne-Zeilinger (GHZ) states. We study the case in which each qubit interacts with a local amplitude damping channel. It is shown that only one type of GHZ state loses its entanglement in finite time; for the rest, N-partite entanglement dies out asymptotically. Algebraic formulas for the entanglement dynamics are given in both cases. We directly confirm that the half-life of the entanglement is proportional to the inverse of N. When entanglement vanishes in finite time, the time at which entanglement vanishes can decrease or increase with N depending on the initial state. In the macroscopic limit, this time is independent of the initial entanglement.

  20. All-optical reversible logic gates with microresonators

    NASA Astrophysics Data System (ADS)

    Sethi, Purnima; Roy, Sukhdev; Topolancik, Juraj; Vollmer, Frank

    2011-08-01

    We present designs of all-optical reversible logic gates, namely, Feynman, Toffoli, Peres and Feynman Double gates, based on switching of a near-IR (1310/1550 nm) signal by low-power control signals at 532 nm and 405 nm, in optically controlled bacteriorhodopsin protein-coated silica microcavities coupled between two tapered single-mode fibers.

  1. All-versus-nothing proofs with n qubits distributed between m parties

    SciTech Connect

    Cabello, Adan; Moreno, Pilar

    2010-04-15

    All-versus-nothing (AVN) proofs show the conflict between Einstein, Podolsky, and Rosen's elements of reality and the perfect correlations of some quantum states. Given an n-qubit state distributed between m parties, we provide a method with which to decide whether this distribution allows an m-partite AVN proof specific for this state using only single-qubit measurements. We apply this method to some recently obtained n-qubit m-particle states. In addition, we provide all inequivalent AVN proofs with less than nine qubits and a minimum number of parties.

  2. All-versus-nothing proofs with n qubits distributed between m parties

    NASA Astrophysics Data System (ADS)

    Cabello, Adán; Moreno, Pilar

    2010-04-01

    All-versus-nothing (AVN) proofs show the conflict between Einstein, Podolsky, and Rosen’s elements of reality and the perfect correlations of some quantum states. Given an n-qubit state distributed between m parties, we provide a method with which to decide whether this distribution allows an m-partite AVN proof specific for this state using only single-qubit measurements. We apply this method to some recently obtained n-qubit m-particle states. In addition, we provide all inequivalent AVN proofs with less than nine qubits and a minimum number of parties.

  3. Quantum Teleportation of an Arbitrary N-qubit State via GHZ-like States

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Liu, Xing-tong; Wang, Jian; Tang, Chao-jing

    2016-03-01

    Recently Zhu (Int. J. Theor. Phys. 53, 4095, 2014) had shown that using GHZ-like states as quantum channel, it is possible to teleport an arbitrary unknown two-qubit state. We investigate this channel for the teleportation of an arbitrary N-qubit state. The strict proof through mathematical induction is presented and the rule for the receiver to reconstruct the desired state is explicitly derived in the most general case. We also discuss that if a system of quantum secret sharing of classical message is established, our protocol can be transformed to a N-qubit perfect controlled teleportation scheme from the controller's point of view.

  4. Simulation of n-qubit quantum systems. IV. Parametrizations of quantum states, matrices and probability distributions

    NASA Astrophysics Data System (ADS)

    Radtke, T.; Fritzsche, S.

    2008-11-01

    , quantum information science has contributed to our understanding of quantum mechanics and has provided also new and efficient protocols, based on the use of entangled quantum states. To determine the behavior and entanglement of n-qubit quantum registers, symbolic and numerical simulations need to be applied in order to analyze how these quantum information protocols work and which role the entanglement plays hereby. Solution method: Using the computer algebra system Maple, we have developed a set of procedures that support the definition, manipulation and analysis of n-qubit quantum registers. These procedures also help to deal with (unitary) logic gates and (nonunitary) quantum operations that act upon the quantum registers. With the parameterization of various frequently-applied objects, that are implemented in the present version, the program now facilitates a wider range of symbolic and numerical studies. All commands can be used interactively in order to simulate and analyze the evolution of n-qubit quantum systems, both in ideal and noisy quantum circuits. Reasons for new version: In the first version of the FEYNMAN program [1], we implemented the data structures and tools that are necessary to create, manipulate and to analyze the state of quantum registers. Later [2,3], support was added to deal with quantum operations (noisy channels) as an ingredient which is essential for studying the effects of decoherence. With the present extension, we add a number of parametrizations of objects frequently utilized in decoherence and entanglement studies, such that as hermitian and unitary matrices, probability distributions, or various kinds of quantum states. This extension therefore provides the basis, for example, for the optimization of a given function over the set of pure states or the simple generation of random objects. Running time: Most commands that act upon quantum registers with five or less qubits take ⩽10 seconds of processor time on a Pentium 4 processor

  5. Quantum logic gates based on ballistic transport in graphene

    SciTech Connect

    Dragoman, Daniela; Dragoman, Mircea

    2016-03-07

    The paper presents various configurations for the implementation of graphene-based Hadamard, C-phase, controlled-NOT, and Toffoli gates working at room temperature. These logic gates, essential for any quantum computing algorithm, involve ballistic graphene devices for qubit generation and processing and can be fabricated using existing nanolithographical techniques. All quantum gate configurations are based on the very large mean-free-paths of carriers in graphene at room temperature.

  6. Bi-orthogonal mutually unbiased bases for N-qubit systems

    NASA Astrophysics Data System (ADS)

    Díaz, Juan J.; Sainz, Isabel; Klimov, Andrei B.

    2017-02-01

    We have developed a general method for constructing a set of non-orthogonal bases with equal separations between all different basis’ states for N-qubit systems. Using these bases we derive an explicit expression for the optimal tomography in non-orthogonal bases and discuss the amount of non-classical resources required for the bases preparation and the precision of the reconstructed state. The special two-qubit case is analysed separately.

  7. Permutationally Invariant Part of a Density Matrix and Nonseparability of N-Qubit States

    NASA Astrophysics Data System (ADS)

    Gao, Ting; Yan, Fengli; van Enk, S. J.

    2014-05-01

    We consider the concept of "the permutationally invariant (PI) part of a density matrix," which has proven very useful for both efficient quantum state estimation and entanglement characterization of N-qubit systems. We show here that the concept is, in fact, basis dependent but that this basis dependence makes it an even more powerful concept than has been appreciated so far. By considering the PI part ρPI of a general (mixed) N-qubit state ρ, we obtain (i) strong bounds on quantitative nonseparability measures, (ii) a whole hierarchy of multipartite separability criteria (one of which entails a sufficient criterion for genuine N-partite entanglement) that can be experimentally determined by just 2N +1 measurement settings, (iii) a definition of an efficiently measurable degree of separability, which can be used for quantifying a novel aspect of decoherence of N qubits, and (iv) an explicit example that shows there are, for increasing N, genuinely N-partite entangled states lying closer and closer to the maximally mixed state. Moreover, we show that if the PI part of a state is k nonseparable, then so is the actual state. We further argue to add as requirement on any multipartite entanglement measure E that it satisfy E(ρ)≥E(ρPI), even though the operation that maps ρ→ρPI is not local.

  8. Universal Superreplication of Unitary Gates

    NASA Astrophysics Data System (ADS)

    Chiribella, G.; Yang, Y.; Huang, C.

    2015-03-01

    Quantum states obey an asymptotic no-cloning theorem, stating that no deterministic machine can reliably replicate generic sequences of identically prepared pure states. In stark contrast, we show that generic sequences of unitary gates can be replicated deterministically at nearly quadratic rates, with an error vanishing on most inputs except for an exponentially small fraction. The result is not in contradiction with the no-cloning theorem, since the impossibility of deterministically transforming pure states into unitary gates prevents the application of the gate replication protocol to states. In addition to gate replication, we show that N parallel uses of a completely unknown unitary gate can be compressed into a single gate acting on O (log2N ) qubits, leading to an exponential reduction of the amount of quantum communication needed to implement the gate remotely.

  9. Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

    NASA Astrophysics Data System (ADS)

    Liu, Yu-Ling; Man, Zhong-Xiao; Xia, Yun-Jie

    2008-07-01

    A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers( M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Horne-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2 N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.

  10. Generation of N-qubit W states with rf SQUID qubits by adiabatic passage

    SciTech Connect

    Deng, Z. J.; Gao, K. L.; Feng, M.

    2006-12-15

    A simple scheme is presented to generate N-qubit W states with rf superconducting quantum interference devices (SQUIDs) in cavity QED through adiabatic passage. Because of the achievable strong coupling for rf SQUID qubits embedded in cavity QED, we can get the desired state with high success probability. Furthermore, the scheme is insensitive to the position inaccuracy of the rf SQUID. Numerical simulation shows that, by using present experimental techniques, we can achieve our scheme with very high success probability, and the fidelity could eventually be unity with the help of dissipation.

  11. Quantum computing gates via optimal control

    NASA Astrophysics Data System (ADS)

    Atia, Yosi; Elias, Yuval; Mor, Tal; Weinstein, Yossi

    2014-10-01

    We demonstrate the use of optimal control to design two entropy-manipulating quantum gates which are more complex than the corresponding, commonly used, gates, such as CNOT and Toffoli (CCNOT): A two-qubit gate called polarization exchange (PE) and a three-qubit gate called polarization compression (COMP) were designed using GRAPE, an optimal control algorithm. Both gates were designed for a three-spin system. Our design provided efficient and robust nuclear magnetic resonance (NMR) radio frequency (RF) pulses for 13C2-trichloroethylene (TCE), our chosen three-spin system. We then experimentally applied these two quantum gates onto TCE at the NMR lab. Such design of these gates and others could be relevant for near-future applications of quantum computing devices.

  12. Optimal classical-communication-assisted local model of n-qubit Greenberger-Horne-Zeilinger correlations

    SciTech Connect

    Tessier, Tracey E.; Caves, Carlton M.; Deutsch, Ivan H.; Eastin, Bryan; Bacon, Dave

    2005-09-15

    We present a model, motivated by the criterion of reality put forward by Einstein, Podolsky, and Rosen and supplemented by classical communication, which correctly reproduces the quantum-mechanical predictions for measurements of all products of Pauli operators on an n-qubit GHZ state (or 'cat state'). The n-2 bits employed by our model are shown to be optimal for the allowed set of measurements, demonstrating that the required communication overhead scales linearly with n. We formulate a connection between the generation of the local values utilized by our model and the stabilizer formalism, which leads us to conjecture that a generalization of this method will shed light on the content of the Gottesman-Knill theorem.

  13. Multipartite quantum and classical correlations in symmetric n-qubit mixed states

    NASA Astrophysics Data System (ADS)

    Giorgi, Gian Luca; Campbell, Steve

    2016-11-01

    We discuss how to calculate genuine multipartite quantum and classical correlations in symmetric, spatially invariant, mixed n-qubit density matrices. We show that the existence of symmetries greatly reduces the amount of free parameters to be optimized in order to find the optimal measurement that minimizes the conditional entropy in the discord calculation. We apply this approach to the states exhibited dynamically during a thermodynamic protocol to extract maximum work. We also apply the symmetry criterion to a wide class of physically relevant cases of spatially homogeneous noise over multipartite entangled states. Exploiting symmetries we are able to calculate the non-local and genuine quantum features of these states and note some interesting properties.

  14. Separability and entanglement of n-qubit and a qubit and a qudit using Hilbert-Schmidt decompositions

    NASA Astrophysics Data System (ADS)

    Ben-Aryeh, Y.; Mann, A.

    2016-08-01

    Hilbert-Schmidt (HS) decompositions are employed for analyzing systems of n-qubit, and a qubit with a qudit. Negative eigenvalues, obtained by partial-transpose (PT) plus local unitary (PTU) transformations for one qubit from the whole system, are used for indicating entanglement/separability. A sufficient criterion for full separability of the n-qubit and qubit-qudit systems is given. We use the singular value decomposition (SVD) for improving the criterion for full separability. General properties of entanglement and separability are analyzed for a system of a qubit and a qudit and n-qubit systems, with emphasis on maximally disordered subsystems (MDS) (i.e. density matrices for which tracing over any subsystem gives the unit density matrix). A sufficient condition that ρ (MDS) is not separable is that it has an eigenvalue larger than 1/d for a qubit and a qudit, and larger than 1/2n-1 for n-qubit system. The PTU transformation does not change the eigenvalues of the n-qubit MDS density matrices for odd n. Thus, the Peres-Horodecki (PH) criterion does not give any information about entanglement of these density matrices. The PH criterion may be useful for indicating inseparability for even n. The changes of the entanglement and separability properties of the GHZ state, the Braid entangled state and the W state by mixing them with white noise are analyzed by the use of the present methods. The entanglement and separability properties of the GHZ-diagonal density matrices, composed of mixture of 8GHZ density matrices with probabilities pi(i=1,2,…,8), is analyzed as function of these probabilities. In some cases, we show that the PH criterion is both sufficient and necessary.

  15. Classification of general n-qubit states under stochastic local operations and classical communication in terms of the rank of coefficient matrix.

    PubMed

    Li, Xiangrong; Li, Dafa

    2012-05-04

    We solve the entanglement classification under stochastic local operations and classical communication (SLOCC) for general n-qubit states. For two arbitrary pure n-qubit states connected via local operations, we establish an equation between the two coefficient matrices associated with the states. The rank of the coefficient matrix is preserved under SLOCC and gives rise to a simple way of partitioning all the pure states of n qubits into different families of entanglement classes, as exemplified here. When applied to the symmetric states, this approach reveals that all the Dicke states |ℓ,n> with ℓ=1,…,[n/2] are inequivalent under SLOCC.

  16. Enhanced architectures for room-temperature reversible logic gates in graphene

    NASA Astrophysics Data System (ADS)

    Dragoman, Daniela; Dragoman, Mircea

    2014-09-01

    We show that reversible two- and three-input logic gates, such as the universal Toffoli gate, can be implemented with three tilted gate electrodes patterned on a monolayer graphene flake. These reversible gates are based on the unique properties of ballistic charge carriers in graphene, which induce bandgaps in transmission for properly chosen potential barriers. The enhanced architectures for reversible logic gate implementation proposed in this paper offer a remarkable design simplification compared to standard approaches based on field-effect transistor circuits, as well as potential high-frequency operation.

  17. A nanomechanical Fredkin gate.

    PubMed

    Wenzler, Josef-Stefan; Dunn, Tyler; Toffoli, Tommaso; Mohanty, Pritiraj

    2014-01-08

    Irreversible logic operations inevitably discard information, setting fundamental limitations on the flexibility and the efficiency of modern computation. To circumvent the limit imposed by the von Neumann-Landauer (VNL) principle, an important objective is the development of reversible logic gates, as proposed by Fredkin, Toffoli, Wilczek, Feynman, and others. Here, we present a novel nanomechanical logic architecture for implementing a Fredkin gate, a universal logic gate from which any reversible computation can be built. In addition to verifying the truth table, we demonstrate operation of the device as an AND, OR, NOT, and FANOUT gate. Excluding losses due to resonator dissipation and transduction, which will require significant improvement in order to minimize the overall energy cost, our device requires an energy of order 10(4) kT per logic operation, similar in magnitude to state-of-the-art transistor-based technologies. Ultimately, reversible nanomechanical logic gates could play a crucial role in developing highly efficient reversible computers, with implications for efficient error correction and quantum computing.

  18. Lyapunov-Based Feedback Preparation of GHZ Entanglement of N-Qubit Systems.

    PubMed

    Liu, Yanan; Kuang, Sen; Cong, Shuang

    2016-07-09

    The Greenberger-Horne-Zeilinger (GHZ) entangled states are a typical class of entangled states in multiparticle systems and play an important role in the applications of quantum communication and quantum computation. For a general quantum system of N qubits, degenerate measurement operators are often met, which cause the convergence obstacle in the state preparation or stabilization problem. This paper first generalizes the traditional quantum state continuous reduction theory to the case of a degenerate measurement operator and chooses a measurement operator for an arbitrarily given target GHZ entangled state, then presents a state stabilization control strategy based on the Lyapunov method and achieves the feedback preparation of the target GHZ state. In our stabilization strategy, we separate the target GHZ state and all the other GHZ states that often form the equilibrium points of the closed-loop system by dividing the state space into several different regions; and formally design a switching control law between the regions, which contains the control Hamiltonians to be constructed. By analyzing the stability of the closed-loop system in the different regions, we propose a systematic method for constructing the control Hamiltonians and solve the convergence problem caused by the degenerate measurement operator. The global stability of the whole closed-loop stochastic system is strictly proved. Also, we perform some simulation experiments on a three-qubit system and prepare a three-qubit GHZ entangled state. At the same time, the simulation results show the effectiveness of the switching control law and the construction method for the control Hamiltonians proposed in this paper.

  19. Reversible logic gates based on enzyme-biocatalyzed reactions and realized in flow cells: a modular approach.

    PubMed

    Fratto, Brian E; Katz, Evgeny

    2015-05-18

    Reversible logic gates, such as the double Feynman gate, Toffoli gate and Peres gate, with 3-input/3-output channels are realized using reactions biocatalyzed with enzymes and performed in flow systems. The flow devices are constructed using a modular approach, where each flow cell is modified with one enzyme that biocatalyzes one chemical reaction. The multi-step processes mimicking the reversible logic gates are organized by combining the biocatalytic cells in different networks. This work emphasizes logical but not physical reversibility of the constructed systems. Their advantages and disadvantages are discussed and potential use in biosensing systems, rather than in computing devices, is suggested.

  20. Protecting quantum Fisher information of N-qubit GHZ state by weak measurement with flips against dissipation.

    PubMed

    Chen, Yu; Zou, Jian; Long, Zheng-Wen; Shao, Bin

    2017-07-21

    In this paper we propose a scheme by using weak-measurement-based pre- and post-flips (WMPPF) to protect the average quantum Fisher information (QFI) in the independent amplitude-damping channel (ADC) for N-qubit GHZ state and generalized N-qubit GHZ states. We also discuss the weak measurement and quantum measurement reversal (WMQMR) with the same ADC. Based on the analytical and numerical results we obtain the main result: the WMPPF can reduce the effect of dissipation on the average QFI of the phase or the frequency for GHZ state and some generalized GHZ states, and the WMQMR can reduce the effect of dissipation on the average fidelity for GHZ state and generalized GHZ states in ADC. Comparing QFI with fidelity for WMPPF or for WMQMR, a scheme protecting the average fidelity does not necessarily protect the average QFI, even with the same parameters, and vice versa. We also focus on the average QFI versus N in the phase estimation and the frequency estimation of WMPPF, both of which show the advantages over the do-nothing (DN) case. From the investigation of the QFI of weight factor, we find that increasing qubit number can protect it both for WMPPF and for DN.

  1. Universal quantum gates for hybrid system assisted by atomic ensembles embedded in double-sided optical cavities

    NASA Astrophysics Data System (ADS)

    Liu, A.-Peng; Cheng, Liu-Yong; Guo, Qi; Zhang, Shou; Zhao, Ming-Xia

    2017-03-01

    We propose deterministic schemes for controlled-NOT (CNOT), Toffoli, and Fredkin gates between flying photon qubits and the collective spin wave (magnon) of an atomic ensemble inside double-sided optical microcavities. All the gates can be accomplished with 100% success probability in principle and no additional qubit is required. Atomic ensemble is employed so that light-matter coupling is remarkably improved by collective enhancement. We qualified the performance of the gates and the results show that they can be faithfully constituted with current experimental techniques.

  2. Universal quantum gates for hybrid system assisted by atomic ensembles embedded in double-sided optical cavities

    PubMed Central

    Liu, A.-Peng; Cheng, Liu-Yong; Guo, Qi; Zhang, Shou; Zhao, Ming-Xia

    2017-01-01

    We propose deterministic schemes for controlled-NOT (CNOT), Toffoli, and Fredkin gates between flying photon qubits and the collective spin wave (magnon) of an atomic ensemble inside double-sided optical microcavities. All the gates can be accomplished with 100% success probability in principle and no additional qubit is required. Atomic ensemble is employed so that light-matter coupling is remarkably improved by collective enhancement. We qualified the performance of the gates and the results show that they can be faithfully constituted with current experimental techniques. PMID:28272548

  3. Universal quantum gates for photon-atom hybrid systems assisted by bad cavities.

    PubMed

    Wang, Guan-Yu; Liu, Qian; Wei, Hai-Rui; Li, Tao; Ai, Qing; Deng, Fu-Guo

    2016-04-12

    We present two deterministic schemes for constructing a CNOT gate and a Toffoli gate on photon-atom and photon-atom-atom hybrid quantum systems assisted by bad cavities, respectively. They are achieved by cavity-assisted photon scattering and work in the intermediate coupling region with bad cavities, which relaxes the difficulty of their implementation in experiment. Also, bad cavities are feasible for fast quantum operations and reading out information. Compared with previous works, our schemes do not need any auxiliary qubits and measurements. Moreover, the schematic setups for these gates are simple, especially that for our Toffoli gate as only a quarter wave packet is used to interact the photon with each of the atoms every time. These atom-cavity systems can be used as the quantum nodes in long-distance quantum communication as their relatively long coherence time is suitable for multi-time operations between the photon and the system. Our calculations show that the average fidelities and efficiencies of our two universal hybrid quantum gates are high with current experimental technology.

  4. Universal quantum gates for photon-atom hybrid systems assisted by bad cavities

    PubMed Central

    Wang, Guan-Yu; Liu, Qian; Wei, Hai-Rui; Li, Tao; Ai, Qing; Deng, Fu-Guo

    2016-01-01

    We present two deterministic schemes for constructing a CNOT gate and a Toffoli gate on photon-atom and photon-atom-atom hybrid quantum systems assisted by bad cavities, respectively. They are achieved by cavity-assisted photon scattering and work in the intermediate coupling region with bad cavities, which relaxes the difficulty of their implementation in experiment. Also, bad cavities are feasible for fast quantum operations and reading out information. Compared with previous works, our schemes do not need any auxiliary qubits and measurements. Moreover, the schematic setups for these gates are simple, especially that for our Toffoli gate as only a quarter wave packet is used to interact the photon with each of the atoms every time. These atom-cavity systems can be used as the quantum nodes in long-distance quantum communication as their relatively long coherence time is suitable for multi-time operations between the photon and the system. Our calculations show that the average fidelities and efficiencies of our two universal hybrid quantum gates are high with current experimental technology. PMID:27067992

  5. Hybrid quantum gates between flying photon and diamond nitrogen-vacancy centers assisted by optical microcavities

    PubMed Central

    Wei, Hai-Rui; Lu Long, Gui

    2015-01-01

    Hybrid quantum gates hold great promise for quantum information processing since they preserve the advantages of different quantum systems. Here we present compact quantum circuits to deterministically implement controlled-NOT, Toffoli, and Fredkin gates between a flying photon qubit and diamond nitrogen-vacancy (NV) centers assisted by microcavities. The target qubits of these universal quantum gates are encoded on the spins of the electrons associated with the diamond NV centers and they have long coherence time for storing information, and the control qubit is encoded on the polarizations of the flying photon and can be easily manipulated. Our quantum circuits are compact, economic, and simple. Moreover, they do not require additional qubits. The complexity of our schemes for universal three-qubit gates is much reduced, compared to the synthesis with two-qubit entangling gates. These schemes have high fidelities and efficiencies, and they are feasible in experiment. PMID:26271899

  6. High-fidelity single-shot three-qubit gates via machine learning

    NASA Astrophysics Data System (ADS)

    Zahedinejad, Ehsan; Ghosh, Joydip; Sanders, Barry C.

    Three-qubit quantum gates play a crucial role in quantum error correction and quantum information processing. Here I discuss how to generate policies for quantum control to design three-qubit gates namely, Toffoli, Controlled-Not-Not and Fredkin gates for an architecture of nearest-neighbor-coupled superconducting artificial atoms. The resulted fidelity for each gate is above the 99.9% which is the threshold fidelity for fault-tolerant quantum computing. We test our policy in the presence of decoherence-induced noise as well as show its robustness under random external noise. The three-qubit gates are designed via our machine learning algorithm called Subspace-Selective Self-Adaptive Differential Evolution (SuSSADE). NSERC, AITF and University of Calgarys Eyes High Fellowship Program.

  7. Designing High-Fidelity Single-Shot Three-Qubit Gates: A Machine-Learning Approach

    NASA Astrophysics Data System (ADS)

    Zahedinejad, Ehsan; Ghosh, Joydip; Sanders, Barry C.

    2016-11-01

    Three-qubit quantum gates are key ingredients for quantum error correction and quantum-information processing. We generate quantum-control procedures to design three types of three-qubit gates, namely Toffoli, controlled-not-not, and Fredkin gates. The design procedures are applicable to a system comprising three nearest-neighbor-coupled superconducting artificial atoms. For each three-qubit gate, the numerical simulation of the proposed scheme achieves 99.9% fidelity, which is an accepted threshold fidelity for fault-tolerant quantum computing. We test our procedure in the presence of decoherence-induced noise and show its robustness against random external noise generated by the control electronics. The three-qubit gates are designed via the machine-learning algorithm called subspace-selective self-adaptive differential evolution.

  8. Universal Fault-Tolerant Gates on Concatenated Stabilizer Codes

    NASA Astrophysics Data System (ADS)

    Yoder, Theodore J.; Takagi, Ryuji; Chuang, Isaac L.

    2016-07-01

    It is an oft-cited fact that no quantum code can support a set of fault-tolerant logical gates that is both universal and transversal. This no-go theorem is generally responsible for the interest in alternative universality constructions including magic state distillation. Widely overlooked, however, is the possibility of nontransversal, yet still fault-tolerant, gates that work directly on small quantum codes. Here, we demonstrate precisely the existence of such gates. In particular, we show how the limits of nontransversality can be overcome by performing rounds of intermediate error correction to create logical gates on stabilizer codes that use no ancillas other than those required for syndrome measurement. Moreover, the logical gates we construct, the most prominent examples being Toffoli and controlled-controlled-Z , often complete universal gate sets on their codes. We detail such universal constructions for the smallest quantum codes, the 5-qubit and 7-qubit codes, and then proceed to generalize the approach. One remarkable result of this generalization is that any nondegenerate stabilizer code with a complete set of fault-tolerant single-qubit Clifford gates has a universal set of fault-tolerant gates. Another is the interaction of logical qubits across different stabilizer codes, which, for instance, implies a broadly applicable method of code switching.

  9. Experimentally feasible set of criteria detecting genuine multipartite entanglement in n-qubit Dicke states and in higher-dimensional systems

    SciTech Connect

    Huber, Marcus; Erker, Paul; Schimpf, Hans; Gabriel, Andreas; Hiesmayr, Beatrix

    2011-04-15

    We construct a set of criteria detecting genuine multipartite entanglement in arbitrary dimensional multipartite systems. These criteria are optimally suited for detecting multipartite entanglement in n-qubit Dicke states with m excitations, as shown in exemplary cases. Furthermore, they can be employed to detect multipartite entanglement in different states related to quantum cloning, decoherence-free communication, and quantum secret sharing. In a detailed analysis, we show that the criteria are also more robust to noise than any other criterion known so far, especially with increasing system size. Furthermore, it is shown that the number of required local observables scales only polynomially with size, thus making the criteria experimentally feasible.

  10. Universal quantum gates on electron-spin qubits with quantum dots inside single-side optical microcavities.

    PubMed

    Wei, Hai-Rui; Deng, Fu-Guo

    2014-01-13

    We present some compact quantum circuits for a deterministic quantum computing on electron-spin qubits assisted by quantum dots inside single-side optical microcavities, including the CNOT, Toffoli, and Fredkin gates. They are constructed by exploiting the giant optical Faraday rotation induced by a single-electron spin in a quantum dot inside a single-side optical microcavity as a result of cavity quantum electrodynamics. Our universal quantum gates have some advantages. First, all the gates are accomplished with a success probability of 100% in principle. Second, our schemes require no additional electron-spin qubits and they are achieved by some input-output processes of a single photon. Third, our circuits for these gates are simple and economic. Moreover, our devices for these gates work in both the weak coupling and the strong coupling regimes, and they are feasible in experiment.

  11. Fractional revivals, multiple-Schrödinger-cat states, and quantum carpets in the interaction of a qubit with N qubits

    NASA Astrophysics Data System (ADS)

    Dooley, Shane; Spiller, Timothy P.

    2014-07-01

    We study the dynamics of a system comprised of a single qubit interacting equally with N qubits (a "spin star" system). Although this model can be solved exactly, the exact solution does not give much intuition for the dynamics of the model. Here, we find an approximation that gives some insight into the dynamics for a particular class of initial spin-coherent states of the N qubits. We find an effective Hamiltonian for the system that is a finite Kerr (one-axis twisting) Hamiltonian for the N +1 qubits. The initial spin-coherent state evolves to spin-squeezed states on short time scales, and to "multiple-Schrödinger-cat" states (superpositions of many spin-coherent states) on longer time scales, a manifestation of the phenomenon of fractional revivals of the initial state. The evolution of the system is visualized with phase-space plots (Q functions) that, when plotted against time, reveal a "quantum carpet" pattern. Of particular interest is the fact that our approximation captures the qualitative features of the model even for small values of N. This suggests the possibility of observing the phenomenon of fractional revival in this model for systems of few qubits.

  12. Grover-algorithm-like operator using only single-qubit gates

    SciTech Connect

    Kato, G.

    2005-09-15

    We propose a quantum circuit for the quantum search problem. The quantum circuit is superior to Grover's algorithm in some realistic cases. The reasons for the superiority are in short as follows: In the quantum circuit proposed in this paper, all the operators except for the oracle can be written as direct products of single-qubit gates. Such separable operators can be executed much faster than multiparticle operators, such as controlled-NOT gates and Toffoli gates, in many realistic systems. The idea of this quantum circuit is inspired by the Hamiltonian used in the adiabatic quantum computer. In addition, the scaling of the number of oracle calls for this circuit is the same as that for Grover's algorithm, i.e., O(2{sup n/2})

  13. Maximal success probabilities of linear-optical quantum gates

    NASA Astrophysics Data System (ADS)

    Uskov, Dmitry B.; Kaplan, Lev; Smith, A. Matthew; Huver, Sean D.; Dowling, Jonathan P.

    2009-04-01

    Numerical optimization is used to design linear-optical devices that implement a desired quantum gate with perfect fidelity, while maximizing the success rate. For the two-qubit controlled-sign [or controlled NOT (CNOT)] gate, we provide numerical evidence that the maximum success rate is S=2/27 using two unentangled ancilla resources; interestingly, additional ancilla resources do not increase the success rate. For the three-qubit Toffoli gate, we show that perfect fidelity is obtained with only three unentangled ancilla photons—less than in any existing scheme—with a maximum S=0.00340 . This compares well to S=(2/27)2/2≈0.00274 , obtainable by combining two CNOT gates and a passive quantum filter [T. C. Ralph, K. J. Resch, and A. Gilchrist, Phys. Rev. A 75, 022313 (2007)]. The general optimization approach can easily be applied to other areas of interest, such as quantum error correction, cryptography, and metrology [M. M. Wilde and D. B. Uskov, Phys. Rev. A 79, 022305 (2009); G. A. Durkin and J. P. Dowling, Phys. Rev. Lett. 99, 070801 (2007)].

  14. Implementation of all-optical reversible logic gate based on holographic laser induced grating using azo-dye doped polymers

    NASA Astrophysics Data System (ADS)

    Forsati, Rana; Valipour Ebrahimi, Sara; Navi, Keivan; Mohajerani, Ezeddin; Jashnsaz, Hossein

    2013-02-01

    Increasing demand for power reduction in computer systems has led to new trends in computations and computer design including reversible computing. Its main aim is to eliminate power dissipation in logical elements but can have some other advantages such as data security and error prevention. Because of interesting properties of reversible computing, implementing computing devices with reversible manner is the only way to make the reversible computing a reality. In recent years, reversible logic has turned out to be a promising computing paradigm having application in CMOS, nanotechnology, quantum computing and optical computing. In this paper, we propose and realize a novel implementation of Toffoli gate in all-optical domain. We have explained its principle of operations and described an actual experimental implementation. The all-optical reversible gate presented in this paper will be useful in different applications such as arithmetic and logical operations in the domain of reversible logic-based computing.

  15. 20. DETAIL VIEW OF SUBMERSIBLE GATE, SHOWING GATE ARMS, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. DETAIL VIEW OF SUBMERSIBLE GATE, SHOWING GATE ARMS, GATE PIERS, TRUNNION PIN AND GATE GAUGE, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  16. 21. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ARM, TRUNNION PIN, PIER AND GATE GAUGE, LOOKING EAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  17. 17. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF NON-SUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ARMS, PIERS AND DAM BRIDGE, WITH ROLLER GATE HEADHOUSE IN BACKGROUND, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  18. 17. DETAIL VIEW OF TAINTER GATE, SHOWING GATES, GATE ARMS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF TAINTER GATE, SHOWING GATES, GATE ARMS, PIERS, GATE CHAINS AND SWITCHES, AND BRIDGE GIRDERS, LOOKING SOUTHWEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  19. 18. DETAIL VIEW OF TAINTER GATE, SHOWING GATES, GATE ARMS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAIL VIEW OF TAINTER GATE, SHOWING GATES, GATE ARMS, PIERS, GATE CHAINS AND SWITCHES, AND BRIDGE GIRDERS, LOOKING NORTHWEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  20. Heralded quantum controlled-phase gates with dissipative dynamics in macroscopically distant resonators

    NASA Astrophysics Data System (ADS)

    Qin, Wei; Wang, Xin; Miranowicz, Adam; Zhong, Zhirong; Nori, Franco

    2017-07-01

    Heralded near-deterministic multiqubit controlled-phase gates with integrated error detection have recently been proposed by Borregaard et al. [Phys. Rev. Lett. 114, 110502 (2015), 10.1103/PhysRevLett.114.110502]. This protocol is based on a single four-level atom (a heralding quartit) and N three-level atoms (operational qutrits) coupled to a single-resonator mode acting as a cavity bus. Here we generalize this method for two distant resonators without the cavity bus between the heralding and operational atoms. Specifically, we analyze the two-qubit controlled-Z gate and its multiqubit-controlled generalization (i.e., a Toffoli-like gate) acting on the two-lowest levels of N qutrits inside one resonator, with their successful actions being heralded by an auxiliary microwave-driven quartit inside the other resonator. Moreover, we propose a circuit-quantum-electrodynamics realization of the protocol with flux and phase qudits in linearly coupled transmission-line resonators with dissipation. These methods offer a quadratic fidelity improvement compared to cavity-assisted deterministic gates.

  1. 16. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ARM, TRUNNION PIN AND PIER, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  2. 18. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAIL VIEW OF NON-SUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ARMS, PIERS AND DAM BRIDGE, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  3. Complete all-optical processing polarization-based binary logic gates and optical processors.

    PubMed

    Zaghloul, Y A; Zaghloul, A R M

    2006-10-16

    -input gates, and sequential and non-sequential Boolean expressions are presented and discussed. The operation of each design is simply understood by a bullet train traveling at the speed of light on a railroad system preconditioned by the crossover states predetermined by the control inputs. The presented designs allow for optical processing of the information eliminating the need to convert it, back and forth, to an electronic signal for processing purposes. All gates with a truth table, including for example Fredkin, Toffoli, testable reversible logic, and threshold logic gates, can be designed and implemented using the railroad architecture. That includes any future gates not known today. Those designs and the quantum gates are not discussed in this paper.

  4. Complete all-optical processing polarization-based binary logic gates and optical processors

    NASA Astrophysics Data System (ADS)

    Zaghloul, Y. A.; Zaghloul, A. R. M.

    2006-10-01

    -input gates, and sequential and non-sequential Boolean expressions are presented and discussed. The operation of each design is simply understood by a bullet train traveling at the speed of light on a railroad system preconditioned by the crossover states predetermined by the control inputs. The presented designs allow for optical processing of the information eliminating the need to convert it, back and forth, to an electronic signal for processing purposes. All gates with a truth table, including for example Fredkin, Toffoli, testable reversible logic, and threshold logic gates, can be designed and implemented using the railroad architecture. That includes any future gates not known today. Those designs and the quantum gates are not discussed in this paper.

  5. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Gate arm and gate mechanism. 234.255 Section 234... Maintenance, Inspection, and Testing Inspections and Tests § 234.255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall...

  6. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Gate arm and gate mechanism. 234.255 Section 234....255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be observed for proper operation at least once each month....

  7. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Gate arm and gate mechanism. 234.255 Section 234....255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be observed for proper operation at least once each month....

  8. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Gate arm and gate mechanism. 234.255 Section 234... Maintenance, Inspection, and Testing Inspections and Tests § 234.255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall...

  9. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Gate arm and gate mechanism. 234.255 Section 234....255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be observed for proper operation at least once each month....

  10. 21. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE ARM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE ARM, GATE PIER, TRUNNION PIN AND GATE GAUGE, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  11. 6. DETAIL VIEW OF ENTRANCE GATES, SHOWING IRON GATE, STONE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. DETAIL VIEW OF ENTRANCE GATES, SHOWING IRON GATE, STONE WORK, AND GATE STOP FROM SOUTHEAST OF NORTHWEST ELEMENTS. - William Enston Home, Entrance Gate, 900 King Street, Charleston, Charleston County, SC

  12. Parallelizable adiabatic gate teleportation

    NASA Astrophysics Data System (ADS)

    Nakago, Kosuke; Hajdušek, Michal; Nakayama, Shojun; Murao, Mio

    2015-12-01

    To investigate how a temporally ordered gate sequence can be parallelized in adiabatic implementations of quantum computation, we modify adiabatic gate teleportation, a model of quantum computation proposed by Bacon and Flammia [Phys. Rev. Lett. 103, 120504 (2009), 10.1103/PhysRevLett.103.120504], to a form deterministically simulating parallelized gate teleportation, which is achievable only by postselection. We introduce a twisted Heisenberg-type interaction Hamiltonian, a Heisenberg-type spin interaction where the coordinates of the second qubit are twisted according to a unitary gate. We develop parallelizable adiabatic gate teleportation (PAGT) where a sequence of unitary gates is performed in a single step of the adiabatic process. In PAGT, numeric calculations suggest the necessary time for the adiabatic evolution implementing a sequence of L unitary gates increases at most as O (L5) . However, we show that it has the interesting property that it can map the temporal order of gates to the spatial order of interactions specified by the final Hamiltonian. Using this property, we present a controlled-PAGT scheme to manipulate the order of gates by a control qubit. In the controlled-PAGT scheme, two differently ordered sequential unitary gates F G and G F are coherently performed depending on the state of a control qubit by simultaneously applying the twisted Heisenberg-type interaction Hamiltonians implementing unitary gates F and G . We investigate why the twisted Heisenberg-type interaction Hamiltonian allows PAGT. We show that the twisted Heisenberg-type interaction Hamiltonian has an ability to perform a transposed unitary gate by just modifying the space ordering of the final Hamiltonian implementing a unitary gate in adiabatic gate teleportation. The dynamics generated by the time-reversed Hamiltonian represented by the transposed unitary gate enables deterministic simulation of a postselected event of parallelized gate teleportation in adiabatic

  13. Quantum gate decomposition algorithms.

    SciTech Connect

    Slepoy, Alexander

    2006-07-01

    Quantum computing algorithms can be conveniently expressed in a format of a quantum logical circuits. Such circuits consist of sequential coupled operations, termed ''quantum gates'', or quantum analogs of bits called qubits. We review a recently proposed method [1] for constructing general ''quantum gates'' operating on an qubits, as composed of a sequence of generic elementary ''gates''.

  14. Gated strip proportional detector

    DOEpatents

    Morris, Christopher L.; Idzorek, George C.; Atencio, Leroy G.

    1987-01-01

    A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10.sup.6. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

  15. Gated strip proportional detector

    DOEpatents

    Morris, C.L.; Idzorek, G.C.; Atencio, L.G.

    1985-02-19

    A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10/sup 6/. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

  16. One, Two, and n Qubit Decoherence

    NASA Astrophysics Data System (ADS)

    Pineda, Carlos

    2007-11-01

    We study decoherence of one, two, and n non-interacting qubits. Decoherence, measured in terms of purity, is calculated in linear response approximation, making use of the spectator configuration. The environment and its interaction with the qubits are modelled by random matrices. For two qubits, numerical studies reveal a simple one to one correspondence between its decoherence and its internal entanglement decay. Using this relation we are able to give a formula for concurrence decay. For large environments the evolution induces a unital channel in the two qubits, providing a partial explanation for the relation above. Using a kicked Ising spin network, we study the exact evolution of two non-interacting qubits in the presence of a spin bath. We find that the entanglement (as measured by concurrence) of the two qubits has a close relation to the purity of the pair, and closely follows an analytic relation derived for Werner states. As a collateral result we find that an integrable environment causes quadratic decay of concurrence as well as of purity, while a chaotic environment causes linear decay. Both quantities display recurrences in some integrable environments. Good agreement with the results found using random matrix theory is obtained. Finally, we analyze decoherence of a quantum register in the absence of non-local operations. The problem is solved in terms of a sum rule which implies linear scaling in the number of qubits. Each term involves a single qubit and its entanglement with the remaining ones. Two conditions are essential: decoherence must be small and the coupling of different qubits must be uncorrelated in the interaction picture. We apply the result to the random matrix model, and illustrate its reach considering a GHZ state coupled to a spin bath.

  17. Range gated imaging experiments using gated intensifiers

    SciTech Connect

    McDonald, T.E. Jr.; Yates, G.J.; Cverna, F.H.; Gallegos, R.A.; Jaramillo, S.A.; Numkena, D.M.; Payton, J.; Pena-Abeyta, C.R.

    1999-03-01

    A variety of range gated imaging experiments using high-speed gated/shuttered proximity focused microchannel plate image intensifiers (MCPII) are reported. Range gated imaging experiments were conducted in water for detection of submerged mines in controlled turbidity tank test and in sea water for the Naval Coastal Sea Command/US Marine Corps. Field experiments have been conducted consisting of kilometer range imaging of resolution targets and military vehicles in atmosphere at Eglin Air Force Base for the US Air Force, and similar imaging experiments, but in smoke environment, at Redstone Arsenal for the US Army Aviation and Missile Command (AMCOM). Wavelength of the illuminating laser was 532 nm with pulse width ranging from 6 to 12 ns and comparable gate widths. These tests have shown depth resolution in the tens of centimeters range from time phasing reflected LADAR images with MCPII shutter opening.

  18. Optical Logic Gates

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.; Dowler, W. L.

    1985-01-01

    Logic gates for light signals constructed from combinations of prisms, polarizing plates, and quarterwave plates. Optical logic gate performs elementary logic operation on light signals received along two optical fibers. Whether gate performs OR function or exclusive-OR function depends on orientation of analyzer. Nonbinary truth tables also obtained by rotating polarizer or analyzer to other positions or inserting other quarter-wave plates.

  19. 15. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATES AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATES AND GATE ARMS, PIERS AND DAM BRIDGE, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  20. 4. DETAIL VIEW OF TAINTER GATE PIER AND TAINTER GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. DETAIL VIEW OF TAINTER GATE PIER AND TAINTER GATE NO. 7 AND NON-SUBMERSIBLE TAINTER GATES, LOOKING WEST (UPSTREAM) - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  1. 19. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE ARM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE ARM, PIER, TRUNNION PIN AND GATE GAUGE, LOOKING NORTH - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  2. 20. DETAIL VIEW OF TAINTER GATE, SHOWING GATE ARMS, PIERS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. DETAIL VIEW OF TAINTER GATE, SHOWING GATE ARMS, PIERS, TRUNNION PINS, AND GATE GAUGE, LOOKING SOUTHWEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  3. 16. DETAIL VIEW OF TAINTER GATE, SHOWING GATES, PIERS, BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. DETAIL VIEW OF TAINTER GATE, SHOWING GATES, PIERS, BRIDGE GIRDERS AND ROLLER GATE BULKHEADS STORED ON PIER ABUTMENTS, LOOKING WEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  4. 12. DETAIL VIEW OF ROLLER GATE, SHOWING GATE FLANGE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. DETAIL VIEW OF ROLLER GATE, SHOWING GATE FLANGE AND TUBE, ROLLER TRACK, CHAIN AND GATE HEATER, LOOKING EAST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  5. 10. DETAIL VIEW OF ROLLER GATE, SHOWING GATE FLANGE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. DETAIL VIEW OF ROLLER GATE, SHOWING GATE FLANGE AND TUBE, ROLLER TRACK AND GATE HEATER, LOOKING SOUTHWEST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  6. Sliding-gate valve

    DOEpatents

    Usnick, George B.; Ward, Gene T.; Blair, Henry O.; Roberts, James W.; Warner, Terry N.

    1979-01-01

    This invention is a novel valve of the slidable-gate type. The valve is designed especially for long-term use with highly abrasive slurries. The sealing surfaces of the gate are shielded by the valve seats when the valve is fully open or closed, and the gate-to-seat clearance is swept with an inflowing purge gas while the gate is in transit. A preferred form of the valve includes an annular valve body containing an annular seat assembly defining a flow channel. The seat assembly comprises a first seat ring which is slidably and sealably mounted in the body, and a second seat ring which is tightly fitted in the body. These rings cooperatively define an annular gap which, together with passages in the valve body, forms a guideway extending normal to the channel. A plate-type gate is mounted for reciprocation in the guideway between positions where a portion of the plate closes the channel and where a circular aperture in the gate is in register with the channel. The valve casing includes opposed chambers which extend outwardly from the body along the axis of the guideway to accommodate the end portions of the gate. The chambers are sealed from atmosphere; when the gate is in transit, purge gas is admitted to the chambers and flows inwardly through the gate-to-seat-ring, clearance, minimizing buildup of process solids therein. A shaft reciprocated by an external actuator extends into one of the sealed chambers through a shaft seal and is coupled to an end of the gate. Means are provided for adjusting the clearance between the first seat ring and the gate while the valve is in service.

  7. Adiabatically implementing quantum gates

    SciTech Connect

    Sun, Jie; Lu, Songfeng Liu, Fang

    2014-06-14

    We show that, through the approach of quantum adiabatic evolution, all of the usual quantum gates can be implemented efficiently, yielding running time of order O(1). This may be considered as a useful alternative to the standard quantum computing approach, which involves quantum gates transforming quantum states during the computing process.

  8. CCD gate definition process

    NASA Astrophysics Data System (ADS)

    Bluzer

    1986-02-01

    The present invention utilizes a double masking step in a CCD gate definition process to eliminate the re-entrant oxide by using a thin film layer other than photoresist to define the polysilicon gates used by defining the thin film layer with a double masking process before any of the polysilicon gate layer is etched. It is one object of the present invention, therefore, to provide an improved process for CCD gate definition. It is another object of the invention to provide an improved CCD gate definition process wherein a profiled oxide layer is produced over a polysilicon layer without re-entrant oxide regions. It is another object of the invention to provide an improved CCD gate definition process wherein a thin film layer is utilized to define the polysilicon gate layers. It is another object of the invention to provide an improved CCD gate definition process wherein the thin film layer is defined by a double masking process before any polysilicon layer is etched.

  9. Optical NAND gate

    DOEpatents

    Skogen, Erik J.; Raring, James; Tauke-Pedretti, Anna

    2011-08-09

    An optical NAND gate is formed from two pair of optical waveguide devices on a substrate, with each pair of the optical waveguide devices consisting of an electroabsorption modulator and a photodetector. One pair of the optical waveguide devices is electrically connected in parallel to operate as an optical AND gate; and the other pair of the optical waveguide devices is connected in series to operate as an optical NOT gate (i.e. an optical inverter). The optical NAND gate utilizes two digital optical inputs and a continuous light input to provide a NAND function output. The optical NAND gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  10. 18. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAIL VIEW OF NON-SUBMERSIBLE TAINTER GATE, SHOWING GATE AND GATE ARMS, GATE PIER AND DAM BRIDGE, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  11. 17. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF NON-SUBMERSIBLE TAINTER GATE, SHOWING GATE AND GATE ARM, GATE PIER AND DAM BRIDGE, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  12. Optical NOR gate

    DOEpatents

    Skogen, Erik J.; Tauke-Pedretti, Anna

    2011-09-06

    An optical NOR gate is formed from two pair of optical waveguide devices on a substrate, with each pair of the optical waveguide devices consisting of an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical NOR gate utilizes two digital optical inputs and a continuous light input to provide a NOR function digital optical output. The optical NOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  13. Optical XOR gate

    SciTech Connect

    Vawter, G. Allen

    2013-11-12

    An optical XOR gate is formed as a photonic integrated circuit (PIC) from two sets of optical waveguide devices on a substrate, with each set of the optical waveguide devices including an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical XOR gate utilizes two digital optical inputs to generate an XOR function digital optical output. The optical XOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  14. The human respiratory gate

    NASA Technical Reports Server (NTRS)

    Eckberg, Dwain L.

    2003-01-01

    Respiratory activity phasically alters membrane potentials of preganglionic vagal and sympathetic motoneurones and continuously modulates their responsiveness to stimulatory inputs. The most obvious manifestation of this 'respiratory gating' is respiratory sinus arrhythmia, the rhythmic fluctuations of electrocardiographic R-R intervals observed in healthy resting humans. Phasic autonomic motoneurone firing, reflecting the throughput of the system, depends importantly on the intensity of stimulatory inputs, such that when levels of stimulation are low (as with high arterial pressure and sympathetic activity, or low arterial pressure and vagal activity), respiratory fluctuations of sympathetic or vagal firing are also low. The respiratory gate has a finite capacity, and high levels of stimulation override the ability of respiration to gate autonomic responsiveness. Autonomic throughput also depends importantly on other factors, including especially, the frequency of breathing, the rate at which the gate opens and closes. Respiratory sinus arrhythmia is small at rapid, and large at slow breathing rates. The strong correlation between systolic pressure and R-R intervals at respiratory frequencies reflects the influence of respiration on these two measures, rather than arterial baroreflex physiology. A wide range of evidence suggests that respiratory activity gates the timing of autonomic motoneurone firing, but does not influence its tonic level. I propose that the most enduring significance of respiratory gating is its use as a precisely controlled experimental tool to tease out and better understand otherwise inaccessible human autonomic neurophysiological mechanisms.

  15. Advanced insulated gate bipolar transistor gate drive

    DOEpatents

    Short, James Evans; West, Shawn Michael; Fabean, Robert J.

    2009-08-04

    A gate drive for an insulated gate bipolar transistor (IGBT) includes a control and protection module coupled to a collector terminal of the IGBT, an optical communications module coupled to the control and protection module, a power supply module coupled to the control and protection module and an output power stage module with inputs coupled to the power supply module and the control and protection module, and outputs coupled to a gate terminal and an emitter terminal of the IGBT. The optical communications module is configured to send control signals to the control and protection module. The power supply module is configured to distribute inputted power to the control and protection module. The control and protection module outputs on/off, soft turn-off and/or soft turn-on signals to the output power stage module, which, in turn, supplies a current based on the signal(s) from the control and protection module for charging or discharging an input capacitance of the IGBT.

  16. CFTR Gating I

    PubMed Central

    Bompadre, Silvia G.; Ai, Tomohiko; Cho, Jeong Han; Wang, Xiaohui; Sohma, Yoshiro; Li, Min; Hwang, Tzyh-Chang

    2005-01-01

    The CFTR chloride channel is activated by phosphorylation of serine residues in the regulatory (R) domain and then gated by ATP binding and hydrolysis at the nucleotide binding domains (NBDs). Studies of the ATP-dependent gating process in excised inside-out patches are very often hampered by channel rundown partly caused by membrane-associated phosphatases. Since the severed ΔR-CFTR, whose R domain is completely removed, can bypass the phosphorylation-dependent regulation, this mutant channel might be a useful tool to explore the gating mechanisms of CFTR. To this end, we investigated the regulation and gating of the ΔR-CFTR expressed in Chinese hamster ovary cells. In the cell-attached mode, basal ΔR-CFTR currents were always obtained in the absence of cAMP agonists. Application of cAMP agonists or PMA, a PKC activator, failed to affect the activity, indicating that the activity of ΔR-CFTR channels is indeed phosphorylation independent. Consistent with this conclusion, in excised inside-out patches, application of the catalytic subunit of PKA did not affect ATP-induced currents. Similarities of ATP-dependent gating between wild type and ΔR-CFTR make this phosphorylation-independent mutant a useful system to explore more extensively the gating mechanisms of CFTR. Using the ΔR-CFTR construct, we studied the inhibitory effect of ADP on CFTR gating. The Ki for ADP increases as the [ATP] is increased, suggesting a competitive mechanism of inhibition. Single channel kinetic analysis reveals a new closed state in the presence of ADP, consistent with a kinetic mechanism by which ADP binds at the same site as ATP for channel opening. Moreover, we found that the open time of the channel is shortened by as much as 54% in the presence of ADP. This unexpected result suggests another ADP binding site that modulates channel closing. PMID:15767295

  17. 2. CANNON GATES. DETAIL OF NORTHWEST GATE STONE WALL TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. CANNON GATES. DETAIL OF NORTHWEST GATE STONE WALL TO LEFT IS A REMNANT OF THE ORIGINAL FACILITY BOUNDARY FENCE. IT IS CONSTRUCTED IN BLUE PUDDING STONE. - Picatinny Arsenal, State Route 15 near I-80, Dover, Morris County, NJ

  18. 7. DETAIL VIEW OF DAM, SHOWING ROLLER GATES, GATE PIERS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. DETAIL VIEW OF DAM, SHOWING ROLLER GATES, GATE PIERS, HEADHOUSES AND DAM BRIDGE, LOOKING NORTHWEST, UPSTREAM - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  19. Amplifying genetic logic gates.

    PubMed

    Bonnet, Jerome; Yin, Peter; Ortiz, Monica E; Subsoontorn, Pakpoom; Endy, Drew

    2013-05-03

    Organisms must process information encoded via developmental and environmental signals to survive and reproduce. Researchers have also engineered synthetic genetic logic to realize simpler, independent control of biological processes. We developed a three-terminal device architecture, termed the transcriptor, that uses bacteriophage serine integrases to control the flow of RNA polymerase along DNA. Integrase-mediated inversion or deletion of DNA encoding transcription terminators or a promoter modulates transcription rates. We realized permanent amplifying AND, NAND, OR, XOR, NOR, and XNOR gates actuated across common control signal ranges and sequential logic supporting autonomous cell-cell communication of DNA encoding distinct logic-gate states. The single-layer digital logic architecture developed here enables engineering of amplifying logic gates to control transcription rates within and across diverse organisms.

  20. Cardiac gated ventilation

    SciTech Connect

    Hanson, C.W. III; Hoffman, E.A.

    1995-12-31

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart.

  1. Adiabatic gate teleportation.

    PubMed

    Bacon, Dave; Flammia, Steven T

    2009-09-18

    The difficulty in producing precisely timed and controlled quantum gates is a significant source of error in many physical implementations of quantum computers. Here we introduce a simple universal primitive, adiabatic gate teleportation, which is robust to timing errors and many control errors and maintains a constant energy gap throughout the computation above a degenerate ground state space. This construction allows for geometric robustness based upon the control of two independent qubit interactions. Further, our piecewise adiabatic evolution easily relates to the quantum circuit model, enabling the use of standard methods from fault-tolerance theory for establishing thresholds.

  2. Outlet side of gate, showing the Radial Gate, hoist mechanism ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Outlet side of gate, showing the Radial Gate, hoist mechanism and concrete walkway across the canal. The concrete baffle separating the afterbay and the cipoletti weir is in the foreground - Wellton-Mohawk Irrigation System, Radial Gate Check with Drop, Wellton Canal 9.9, West of Avenue 34 East & north of County Ninth Street, Wellton, Yuma County, AZ

  3. Exterior, looking northwest towards Main Gate, Gate House on left, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Exterior, looking northwest towards Main Gate, Gate House on left, Technical Equipment Building (Building 5760) in background to right - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Gate House, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  4. Exterior, looking southeast from within compound towards Main Gate, Gate ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Exterior, looking southeast from within compound towards Main Gate, Gate House center left - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Gate House, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  5. The four-gate transistor

    NASA Technical Reports Server (NTRS)

    Mojarradi, M. M.; Cristoveanu, S.; Allibert, F.; France, G.; Blalock, B.; Durfrene, B.

    2002-01-01

    The four-gate transistor or G4-FET combines MOSFET and JFET principles in a single SOI device. Experimental results reveal that each gate can modulate the drain current. Numerical simulations are presented to clarify the mechanisms of operation. The new device shows enhanced functionality, due to the combinatorial action of the four gates, and opens rather revolutionary applications.

  6. Stanford, Duke, Rice,... and Gates?

    ERIC Educational Resources Information Center

    Carey, Kevin

    2009-01-01

    This article presents an open letter to Bill Gates. In his letter, the author suggests that Bill Gates should build a brand-new university, a great 21st-century institution of higher learning. This university will be unlike anything the world has ever seen. He asks Bill Gates not to stop helping existing colleges create the higher-education system…

  7. The four-gate transistor

    NASA Technical Reports Server (NTRS)

    Mojarradi, M. M.; Cristoveanu, S.; Allibert, F.; France, G.; Blalock, B.; Durfrene, B.

    2002-01-01

    The four-gate transistor or G4-FET combines MOSFET and JFET principles in a single SOI device. Experimental results reveal that each gate can modulate the drain current. Numerical simulations are presented to clarify the mechanisms of operation. The new device shows enhanced functionality, due to the combinatorial action of the four gates, and opens rather revolutionary applications.

  8. Stanford, Duke, Rice,... and Gates?

    ERIC Educational Resources Information Center

    Carey, Kevin

    2009-01-01

    This article presents an open letter to Bill Gates. In his letter, the author suggests that Bill Gates should build a brand-new university, a great 21st-century institution of higher learning. This university will be unlike anything the world has ever seen. He asks Bill Gates not to stop helping existing colleges create the higher-education system…

  9. Nanoparticle Based Logic Gates

    NASA Astrophysics Data System (ADS)

    Berven, Christopher; Wybourne, Martin; Longstreth, Lydia

    2003-05-01

    Ligand stabilized gold nanoparticles have novel properties that can be exploited for their use as possible building blocks for room-temperature single electron devices. With a core of 70 gold atoms or less (diameter <= 1.4 nm), the self-capacitance of these particles is a fraction of an atto-Farad. This small capacitance translates into an electrostatic charging energy well in excess of the thermal energy at room temperature. Single electron behavior has been demonstrated in one- and two-dimensional arrays of nanoparticles. In traditional single electron devices, the self-capacitance is negligible, whereas the self-capacitance in nanoparticle based devices can be the dominant capacitance. This means that the effect of charging a nanoparticle chain is highly localized which is in contrast to traditional single electron devices where the induced potential due to an excess electron on an island is felt by many neighboring islands. As a result, the current-voltage characteristics and plots of stable electron occupancy in the arrays have different behavior to that found in traditional devices. We show that this new regime of tunneling behavior can be exploited to create a novel family of single-electron logic gate devices. Using numerical simulation we have found that when a one-dimensional array of nanoparticles is gated in an electron-pump arrangement and properly biased, the behavior is that of an AND gate. The addition of an inverter circuit results in NAND gate behavior, the inverter providing the power necessary for the cascading of multiple NAND gates and the generation of arbitrary logic circuits.

  10. Noise Gating Solar Images

    NASA Astrophysics Data System (ADS)

    DeForest, Craig; Seaton, Daniel B.; Darnell, John A.

    2017-08-01

    I present and demonstrate a new, general purpose post-processing technique, "3D noise gating", that can reduce image noise by an order of magnitude or more without effective loss of spatial or temporal resolution in typical solar applications.Nearly all scientific images are, ultimately, limited by noise. Noise can be direct Poisson "shot noise" from photon counting effects, or introduced by other means such as detector read noise. Noise is typically represented as a random variable (perhaps with location- or image-dependent characteristics) that is sampled once per pixel or once per resolution element of an image sequence. Noise limits many aspects of image analysis, including photometry, spatiotemporal resolution, feature identification, morphology extraction, and background modeling and separation.Identifying and separating noise from image signal is difficult. The common practice of blurring in space and/or time works because most image "signal" is concentrated in the low Fourier components of an image, while noise is evenly distributed. Blurring in space and/or time attenuates the high spatial and temporal frequencies, reducing noise at the expense of also attenuating image detail. Noise-gating exploits the same property -- "coherence" -- that we use to identify features in images, to separate image features from noise.Processing image sequences through 3-D noise gating results in spectacular (more than 10x) improvements in signal-to-noise ratio, while not blurring bright, resolved features in either space or time. This improves most types of image analysis, including feature identification, time sequence extraction, absolute and relative photometry (including differential emission measure analysis), feature tracking, computer vision, correlation tracking, background modeling, cross-scale analysis, visual display/presentation, and image compression.I will introduce noise gating, describe the method, and show examples from several instruments (including SDO

  11. A quantum Fredkin gate

    PubMed Central

    Patel, Raj B.; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C.; Pryde, Geoff J.

    2016-01-01

    Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently. PMID:27051868

  12. A quantum Fredkin gate.

    PubMed

    Patel, Raj B; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C; Pryde, Geoff J

    2016-03-01

    Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently.

  13. 100-nm gate lithography for double-gate transistors

    NASA Astrophysics Data System (ADS)

    Krasnoperova, Azalia A.; Zhang, Ying; Babich, Inna V.; Treichler, John; Yoon, Jung H.; Guarini, Kathryn; Solomon, Paul M.

    2001-09-01

    The double gate field effect transistor (FET) is an exploratory device that promises certain performance advantages compared to traditional CMOS FETs. It can be scaled down further than the traditional devices because of the greater electrostatic control by the gates on the channel (about twice as short a channel length for the same gate oxide thickness), has steeper sub-threshold slope and about double the current for the same width. This paper presents lithographic results for double gate FET's developed at IBM's T. J. Watson Research Center. The device is built on bonded wafers with top and bottom gates self-aligned to each other. The channel is sandwiched between the top and bottom polysilicon gates and the gate length is defined using DUV lithography. An alternating phase shift mask was used to pattern gates with critical dimensions of 75 nm, 100 nm and 125 nm in photoresist. 50 nm gates in photoresist have also been patterned by 20% over-exposure of nominal 100 nm lines. No trim mask was needed because of a specific way the device was laid out. UV110 photoresist from Shipley on AR-3 antireflective layer were used. Process windows, developed and etched patterns are presented.

  14. Impact of gate geometry on ionic liquid gated ionotronic systems

    NASA Astrophysics Data System (ADS)

    Wong, A. T.; Noh, J. H.; Pudasaini, P. R.; Wolf, B.; Balke, N.; Herklotz, A.; Sharma, Y.; Haglund, A. V.; Dai, S.; Mandrus, D.; Rack, P. D.; Ward, T. Z.

    2017-04-01

    Ionic liquid electrolytes are gaining widespread application as a gate dielectric used to control ion transport in functional materials. This letter systematically examines the important influence that device geometry in standard "side gate" 3-terminal geometries plays in device performance of a well-known oxygen ion conductor. We show that the most influential component of device design is the ratio between the area of the gate electrode and the active channel, while the spacing between these components and their individual shapes has a negligible contribution. These findings provide much needed guidance in device design intended for ionotronic gating with ionic liquids.

  15. Floating gate circuits in MOSIS

    NASA Astrophysics Data System (ADS)

    Mann, James R.

    1990-11-01

    The MOSIS foundry offers a two-poly CMOS process that can be used as a floating gate technology, albeit not with the same performance as commercial EEPROM foundries. This report characterizes the structures and programming techniques necessary to build floating gate structures and associated high-voltage addressing circuitry on the low-noise analog process available through MOSIS. Techniques that are used include Fowler-Nordheim tunneling, channel hot-electron injection, and avalanche injection. The dielectric materials between the floating gate and both the control gate and substrate are characterized. Unconventional lightly doped drain FET devices and additional circuit techniques for handling the high-voltage programming signals are presented.

  16. Compact gate valve

    DOEpatents

    Bobo, Gerald E.

    1977-01-01

    This invention relates to a double-disc gate valve which is compact, comparatively simple to construct, and capable of maintaining high closing pressures on the valve discs with low frictional forces. The valve casing includes axially aligned ports. Mounted in the casing is a sealed chamber which is pivotable transversely of the axis of the ports. The chamber contains the levers for moving the valve discs axially, and an actuator for the levers. When an external drive means pivots the chamber to a position where the discs are between the ports and axially aligned therewith, the actuator for the levers is energized to move the discs into sealing engagement with the ports.

  17. ONE SHAKE GATE FORMER

    DOEpatents

    Kalibjian, R.; Perez-Mendez, V.

    1957-08-20

    An improved circuit for forming square pulses having substantially short and precise durations is described. The gate forming circuit incorporates a secondary emission R. F. pentode adapted to receive input trigger pulses amd having a positive feedback loop comnected from the dynode to the control grid to maintain conduction in response to trigger pulses. A short circuited pulse delay line is employed to precisely control the conducting time of the tube and a circuit for squelching spurious oscillations is provided in the feedback loop.

  18. 16. Little Hell Gate Bridge with Big Hell Gate Bridge ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Little Hell Gate Bridge with Big Hell Gate Bridge in background. Wards Island, New York Co., NY. Sec. 4207, MP 8.02. - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York County, NY

  19. TRP channel gating physiology.

    PubMed

    Nieto-Posadas, Andrés; Jara-Oseguera, Andrés; Rosenbaum, Tamara

    2011-01-01

    Transient Receptor Potential (TRP) cation channels participate in several processes of vital importance in cell and organism physiology, and have been demonstrated to participate in the detection of sensory stimuli. The thermo TRP's reviewed: TRPV1 (vanilloid 1), TRPM8 (melastatin 8) and TRPA1 (ankyrin-like 1) are known to integrate different chemical and physical stimuli such as changes in temperature and sensing different irritant or pungent compounds. However, despite the physiological importance of these channels the mechanisms by which they detect incoming stimuli, how the sensing domains are coupled to channel gating and how these processes are connected to specific structural regions in the channel are not fully understood, but valuable information is available. Many sites involved in agonist detection have been characterized and gating models that describe many features of the channel's behavior have been put forward. In this review we will survey some of the key findings concerning the structural and molecular mechanisms of TRPV1, TRPA1 and TRPM8 activation.

  20. Penn State DOE GATE Program

    SciTech Connect

    Anstrom, Joel

    2012-08-31

    The Graduate Automotive Technology Education (GATE) Program at The Pennsylvania State University (Penn State) was established in October 1998 pursuant to an award from the U.S. Department of Energy (U.S. DOE). The focus area of the Penn State GATE Program is advanced energy storage systems for electric and hybrid vehicles.

  1. Gates Learns to Think Big

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    2006-01-01

    This article discusses how the philanthropy of Microsoft Corp software magnate co-chairs, Bill Gates and his wife Melinda, are reshaping the American high school nowadays. Gates and his wife have put the issue on the national agenda like never before, with a commitment of more than 1.3 billion US dollars this decade toward the foundation's agenda…

  2. Gates Learns to Think Big

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    2006-01-01

    This article discusses how the philanthropy of Microsoft Corp software magnate co-chairs, Bill Gates and his wife Melinda, are reshaping the American high school nowadays. Gates and his wife have put the issue on the national agenda like never before, with a commitment of more than 1.3 billion US dollars this decade toward the foundation's agenda…

  3. On plant roots logical gates.

    PubMed

    Adamatzky, Andrew; Sirakoulis, Georgios Ch; Martínez, Genaro J; Baluška, Frantisek; Mancuso, Stefano

    Theoretical constructs of logical gates implemented with plant roots are morphological computing asynchronous devices. Values of Boolean variables are represented by plant roots. A presence of a plant root at a given site symbolises the logical True, an absence the logical False. Logical functions are calculated via interaction between roots. Two types of two-inputs-two-outputs gates are proposed: a gate 〈x, y〉→〈xy, x+y〉 where root apexes are guided by gravity and a gate 〈x,y〉→〈x¯y,x〉 where root apexes are guided by humidity. We propose a design of binary half-adder based on the gates. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Protected gates for superconducting qubits

    NASA Astrophysics Data System (ADS)

    Brooks, Peter; Kitaev, Alexei; Preskill, John

    2013-05-01

    We analyze the accuracy of quantum phase gates acting on “0-π qubits” in superconducting circuits, where the gates are protected against thermal and Hamiltonian noise by continuous-variable quantum error-correcting codes. The gates are executed by turning on and off a tunable Josephson coupling between an LC oscillator and a qubit or pair of qubits; assuming perfect qubits, we show that the gate errors are exponentially small when the oscillator's impedance L/C is large compared to ℏ/4e2≈1kΩ. The protected gates are not computationally universal by themselves, but a scheme for universal fault-tolerant quantum computation can be constructed by combining them with unprotected noisy operations. We validate our analytic arguments with numerical simulations.

  5. Impact of gate geometry on ionic liquid gated ionotronic systems

    DOE PAGES

    Wong, Anthony T.; Noh, Joo Hyon; Pudasaini, Pushpa Raj; ...

    2017-01-23

    Ionic liquid electrolytes are gaining widespread application as a gate dielectric used to control ion transport in functional materials. This letter systematically examines the important influence that device geometry in standard “side gate” 3-terminal geometries plays in device performance of a well-known oxygen ion conductor. We show that the most influential component of device design is the ratio between the area of the gate electrode and the active channel, while the spacing between these components and their individual shapes has a negligible contribution. Finally, these findings provide much needed guidance in device design intended for ionotronic gating with ionic liquids.

  6. Commentary on WHO GATE Initiative.

    PubMed

    Cooper, Rory A

    2017-01-01

    Assistive technology is essential to people with spinal cord injuries (SCI) for living and participating in their communities. However, many people with SCI do not have access to adequate assistive technology and qualified services. The World Health Organization (WHO) is addressing this need through the Global Cooperation on Assistive Technology (GATE). The GATE initiative is focused on improving access to high-quality affordable AT world-wide. GATE working to meet the AT sector needs in response to the call by WHO to increase access to essential, high-quality, safe, effective and affordable medical devices, which is one of the six WHO leadership priorities.

  7. Superconducting gates with fluxon logics

    NASA Astrophysics Data System (ADS)

    Nacak, H.; Kusmartsev, F. V.

    2010-10-01

    We have developed several logic gates (OR, XOR, AND and NAND) made of superconducting Josephson junctions. The gates based of the flux cloning phenomenon and high speed of fluxons moving in Josephson junctions of different shapes. In a contrast with previous design the gates operates extremely fast since fluxons are moving with the speed close to the speed of light. We have demonstrated their operations and indicated several ways to made a more complicated logic elements which have at the same time a compact form.

  8. Robust Soldier Crab Ball Gate

    NASA Astrophysics Data System (ADS)

    Gunji, Yukio-Pegio; Nishiyama, Yuta; Adamatzky, Andrew

    2011-09-01

    Based on the field observation of soldier crabs, we previously proposed a model for a swarm of soldier crabs. Here, we describe the interaction of coherent swarms in the simulation model, which is implemented in a logical gate. Because a swarm is generated by inherent perturbation, a swarm can be generated and maintained under highly perturbed conditions. Thus, the model reveals a robust logical gate rather than stable one. In addition, we show that the logical gate of swarms is also implemented by real soldier crabs (Mictyris guinotae).

  9. Reversible logic gates on Physarum Polycephalum

    SciTech Connect

    Schumann, Andrew

    2015-03-10

    In this paper, we consider possibilities how to implement asynchronous sequential logic gates and quantum-style reversible logic gates on Physarum polycephalum motions. We show that in asynchronous sequential logic gates we can erase information because of uncertainty in the direction of plasmodium propagation. Therefore quantum-style reversible logic gates are more preferable for designing logic circuits on Physarum polycephalum.

  10. 49 CFR 234.223 - Gate arm.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Gate arm. 234.223 Section 234.223 Transportation... Maintenance Standards § 234.223 Gate arm. Each gate arm, when in the downward position, shall extend across... clearly viewed by approaching highway users. Each gate arm shall start its downward motion not less...

  11. 49 CFR 234.223 - Gate arm.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Gate arm. 234.223 Section 234.223 Transportation... SYSTEMS Maintenance, Inspection, and Testing Maintenance Standards § 234.223 Gate arm. Each gate arm, when... maintained in a condition sufficient to be clearly viewed by approaching highway users. Each gate arm...

  12. 49 CFR 234.223 - Gate arm.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Gate arm. 234.223 Section 234.223 Transportation... Maintenance Standards § 234.223 Gate arm. Each gate arm, when in the downward position, shall extend across... clearly viewed by approaching highway users. Each gate arm shall start its downward motion not less...

  13. 49 CFR 234.223 - Gate arm.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Gate arm. 234.223 Section 234.223 Transportation... SYSTEMS Maintenance, Inspection, and Testing Maintenance Standards § 234.223 Gate arm. Each gate arm, when... maintained in a condition sufficient to be clearly viewed by approaching highway users. Each gate arm...

  14. The Gates, 1979-2005

    ERIC Educational Resources Information Center

    School Arts: The Art Education Magazine for Teachers, 2005

    2005-01-01

    One art critic called it pure Despite the mixed reviews of Christo and Jeanne-Claude's temporary art installation in New York's Central Park, the public reaction to The Gates was largely positive.The Gates consisted of 7,500 orange PVC frames straddling the park's walkways that varied in widths from 5 1/2 feet to 18 feet. Eight-foot-long ripstop…

  15. The Gates, 1979-2005

    ERIC Educational Resources Information Center

    School Arts: The Art Education Magazine for Teachers, 2005

    2005-01-01

    One art critic called it pure Despite the mixed reviews of Christo and Jeanne-Claude's temporary art installation in New York's Central Park, the public reaction to The Gates was largely positive.The Gates consisted of 7,500 orange PVC frames straddling the park's walkways that varied in widths from 5 1/2 feet to 18 feet. Eight-foot-long ripstop…

  16. Quantum gates with topological phases

    SciTech Connect

    Ionicioiu, Radu

    2003-09-01

    We investigate two models for performing topological quantum gates with the Aharonov-Bohm (AB) and Aharonov-Casher (AC) effects. Topological one- and two-qubit Abelian phases can be enacted with the AB effect using charge qubits, whereas the AC effect can be used to perform all single-qubit gates (Abelian and non-Abelian) for spin qubits. Possible experimental setups suitable for a solid-state implementation are briefly discussed.

  17. A molecular logic gate

    PubMed Central

    Kompa, K. L.; Levine, R. D.

    2001-01-01

    We propose a scheme for molecule-based information processing by combining well-studied spectroscopic techniques and recent results from chemical dynamics. Specifically it is discussed how optical transitions in single molecules can be used to rapidly perform classical (Boolean) logical operations. In the proposed way, a restricted number of states in a single molecule can act as a logical gate equivalent to at least two switches. It is argued that the four-level scheme can also be used to produce gain, because it allows an inversion, and not only a switching ability. The proposed scheme is quantum mechanical in that it takes advantage of the discrete nature of the energy levels but, we here discuss the temporal evolution, with the use of the populations only. On a longer time range we suggest that the same scheme could be extended to perform quantum logic, and a tentative suggestion, based on an available experiment, is discussed. We believe that the pumping can provide a partial proof of principle, although this and similar experiments were not interpreted thus far in our terms. PMID:11209046

  18. Logical gates in actin monomer.

    PubMed

    Adamatzky, Andrew

    2017-09-18

    We evaluate information processing capacity of a single actin molecule by calculating distributions of logical gates implemented by the molecule via propagating patterns of excitation. We represent a filamentous actin molecule as an excitable automaton network (F-actin automaton). where every atom updates its state depending on states of atoms its connected to with chemical bonds (hard neighbours) and atoms being in physical proximity to the atom (soft neighbours). A resting atom excites if a sum of its excited hard neighbours and a weighted sum of its soft neighbours belong to some specified interval. We demonstrate that F-actin automata implement OR, AND, XOR and AND-NOT gates via interacting patterns of excitation. Gate AND is the most common gate and gate XOR is the rarest. Using the architectures of gates discovered we implement one bit half-adder and controlled-not circuits in the F-actin automata. Speed and space values of the F-actin molecular computers are discussed.

  19. Latest design of gate valves

    SciTech Connect

    Kurzhofer, U.; Stolte, J.; Weyand, M.

    1996-12-01

    Babcock Sempell, one of the most important valve manufacturers in Europe, has delivered valves for the nuclear power industry since the beginning of the peaceful application of nuclear power in the 1960s. The latest innovation by Babcock Sempell is a gate valve that meets all recent technical requirements of the nuclear power technology. At the moment in the United States, Germany, Sweden, and many other countries, motor-operated gate and globe valves are judged very critically. Besides the absolute control of the so-called {open_quotes}trip failure,{close_quotes} the integrity of all valve parts submitted to operational forces must be maintained. In case of failure of the limit and torque switches, all valve designs have been tested with respect to the quality of guidance of the gate. The guidances (i.e., guides) shall avoid a tilting of the gate during the closing procedure. The gate valve newly designed by Babcock Sempell fulfills all these characteristic criteria. In addition, the valve has cobalt-free seat hardfacing, the suitability of which has been proven by friction tests as well as full-scale blowdown tests at the GAP of Siemens in Karlstein, West Germany. Babcock Sempell was to deliver more than 30 gate valves of this type for 5 Swedish nuclear power stations by autumn 1995. In the presentation, the author will report on the testing performed, qualifications, and sizing criteria which led to the new technical design.

  20. Quantum gate-set tomography

    NASA Astrophysics Data System (ADS)

    Blume-Kohout, Robin

    2014-03-01

    Quantum information technology is built on (1) physical qubits and (2) precise, accurate quantum logic gates that transform their states. Developing quantum logic gates requires good characterization - both in the development phase, where we need to identify a device's flaws so as to fix them, and in the production phase, where we need to make sure that the device works within specs and predict residual error rates and types. This task falls to quantum state and process tomography. But until recently, protocols for tomography relied on a pre-existing and perfectly calibrated reference frame comprising the measurements (and, for process tomography, input states) used to characterize the device. In practice, these measurements are neither independent nor perfectly known - they are usually implemented via exactly the same gates that we are trying to characterize! In the past year, several partial solutions to this self-consistency problem have been proposed. I will present a framework (gate set tomography, or GST) that addresses and resolves this problem, by self-consistently characterizing an entire set of quantum logic gates on a black-box quantum device. In particular, it contains an explicit closed-form protocol for linear-inversion gate set tomography (LGST), which is immune to both calibration error and technical pathologies like local maxima of the likelihood (which plagued earlier methods). GST also demonstrates significant (multiple orders of magnitude) improvements in efficiency over standard tomography by using data derived from long sequences of gates (much like randomized benchmarking). GST has now been applied to qubit devices in multiple technologies. I will present and discuss results of GST experiments in technologies including a single trapped-ion qubit and a silicon quantum dot qubit. Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U

  1. Single event gate rupture in thin gate oxides

    SciTech Connect

    Sexton, F.W.; Fleetwood, D.M.; Shaneyfelt, M.R.; Dodd, P.E.; Hash, G.L.

    1997-06-01

    As integrated circuit densities increase with each new technology generation, both the lateral and vertical dimensions shrink. Operating voltages, however, have not scaled as aggressively as feature size, with a resultant increase in the electric fields within advanced geometry devices. Oxide electric fields are in fact increasing to greater than 5 MV/cm as feature size approaches 0.1 {micro}m. This trend raises the concern that single event gate rupture (SEGR) may limit the scaling of advanced integrated circuits (ICs) for space applications. The dependence of single event gate rupture (SEGR) critical field on oxide thickness is examined for thin gate oxides. Critical field for SEGR increases with decreasing oxide thickness, consistent with an increasing intrinsic breakdown field.

  2. Prospectively gated cardiac computed tomography.

    PubMed

    Moore, S C; Judy, P F; Garnic, J D; Kambic, G X; Bonk, F; Cochran, G; Margosian, P; McCroskey, W; Foote, F

    1983-01-01

    A fourth-generation scanner has been modified to perform prospectively gated cardiac computed tomography (CT). A computer program monitors the electrocardiogram (ECG) and predicts when to initiate the next scan in a gated series in order to acquire all projection data for a desired phase of the heart cycle. The system has been tested with dogs and has produced cross-sectional images of all phases of the cardiac cycle. Eight to ten scans per series were sufficient to obtain reproducible images of each transverse section in the end-diastolic and end-systolic phases. The radiation dose to the skin was approximately 1.4 cGy per scan. The prospectively gated system is more than twice as efficient as a retrospectively gated system in obtaining complete angular projection data for a 10% heart cycle window. A temporal smoothing technique to suppress reconstruction artifacts due to sorting inconsistent projection data was developed and evaluated. Image noise was reduced by averaging together any overlapping projection data. Prospectively gated cardiac CT has also been used to demonstrate that the error in attenuation measured with a single nongated CT scan through the heart can be as large as 50-60 CT numbers outside the heart in the lung field.

  3. Operational entanglement families of symmetric mixed N -qubit states

    NASA Astrophysics Data System (ADS)

    Bastin, T.; Mathonet, P.; Solano, E.

    2015-02-01

    We introduce an operational entanglement classification of symmetric mixed states for an arbitrary number of qubits based on stochastic local operations assisted with classical communication (SLOCC operations). We define families of SLOCC entanglement classes successively embedded into each other, we prove that they are of nonzero measure, and we construct witness operators to distinguish them. Moreover, we discuss how arbitrary symmetric mixed states can be realized in the laboratory via a one-to-one correspondence between well-defined sets of controllable parameters and the corresponding entanglement families.

  4. Quantum gates by periodic driving

    PubMed Central

    Shi, Z. C.; Wang, W.; Yi, X. X.

    2016-01-01

    Topological quantum computation has been extensively studied in the past decades due to its robustness against decoherence. One way to realize the topological quantum computation is by adiabatic evolutions—it requires relatively long time to complete a gate, so the speed of quantum computation slows down. In this work, we present a method to realize single qubit quantum gates by periodic driving. Compared to adiabatic evolution, the single qubit gates can be realized at a fixed time much shorter than that by adiabatic evolution. The driving fields can be sinusoidal or square-well field. With the sinusoidal driving field, we derive an expression for the total operation time in the high-frequency limit, and an exact analytical expression for the evolution operator without any approximations is given for the square well driving. This study suggests that the period driving could provide us with a new direction in regulations of the operation time in topological quantum computation. PMID:26911900

  5. Ionic thermoelectric gating organic transistors

    NASA Astrophysics Data System (ADS)

    Zhao, Dan; Fabiano, Simone; Berggren, Magnus; Crispin, Xavier

    2017-01-01

    Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (~100 μV K-1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (~10,000 μV K-1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins.

  6. Electrostatic Gating of Ultrathin Films

    NASA Astrophysics Data System (ADS)

    Goldman, A. M.

    2014-07-01

    Electrostatic gating of ultrathin films can be used to modify electronic and magnetic properties of materials by effecting controlled alterations of carrier concentration while, in principle, not changing the level of disorder. As such, electrostatic gating can facilitate the development of novel devices and can serve as a means of exploring the fundamental properties of materials in a manner far simpler than is possible with the conventional approach of chemical doping. The entire phase diagram of a compound can be traversed by changing the gate voltage. In this review, we survey results involving conventional field effect devices as well as more recent progress, which has involved structures that rely on electrochemical configurations such as electric double-layer transistors. We emphasize progress involving thin films of oxide materials such as high-temperature superconductors, magnetic oxides, and oxides that undergo metal-insulator transitions.

  7. Ionic thermoelectric gating organic transistors

    PubMed Central

    Zhao, Dan; Fabiano, Simone; Berggren, Magnus; Crispin, Xavier

    2017-01-01

    Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (∼100 μV K−1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (∼10,000 μV K−1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins. PMID:28139738

  8. Localizing a gate in CFTR

    PubMed Central

    Gao, Xiaolong; Hwang, Tzyh-Chang

    2015-01-01

    Experimental and computational studies have painted a picture of the chloride permeation pathway in cystic fibrosis transmembrane conductance regulator (CFTR) as a short narrow tunnel flanked by wider inner and outer vestibules. Although these studies also identified a number of transmembrane segments (TMs) as pore-lining, the exact location of CFTR’s gate(s) remains unknown. Here, using a channel-permeant probe, [Au(CN)2]−, we provide evidence that CFTR bears a gate that coincides with the predicted narrow section of the pore defined as residues 338–341 in TM6. Specifically, cysteines introduced cytoplasmic to the narrow region (i.e., positions 344 in TM6 and 1148 in TM12) can be modified by intracellular [Au(CN)2]− in both open and closed states, corroborating the conclusion that the internal vestibule does not harbor a gate. However, cysteines engineered to positions external to the presumed narrow region (e.g., 334, 335, and 337 in TM6) are all nonreactive toward cytoplasmic [Au(CN)2]− in the absence of ATP, whereas they can be better accessed by extracellular [Au(CN)2]− when the open probability is markedly reduced by introducing a second mutation, G1349D. As [Au(CN)2]− and chloride ions share the same permeation pathway, these results imply a gate is situated between amino acid residues 337 and 344 along TM6, encompassing the very segment that may also serve as the selectivity filter for CFTR. The unique position of a gate in the middle of the ion translocation pathway diverges from those seen in ATP-binding cassette (ABC) transporters and thus distinguishes CFTR from other members of the ABC transporter family. PMID:25675504

  9. Localizing a gate in CFTR.

    PubMed

    Gao, Xiaolong; Hwang, Tzyh-Chang

    2015-02-24

    Experimental and computational studies have painted a picture of the chloride permeation pathway in cystic fibrosis transmembrane conductance regulator (CFTR) as a short narrow tunnel flanked by wider inner and outer vestibules. Although these studies also identified a number of transmembrane segments (TMs) as pore-lining, the exact location of CFTR's gate(s) remains unknown. Here, using a channel-permeant probe, [Au(CN)2](-), we provide evidence that CFTR bears a gate that coincides with the predicted narrow section of the pore defined as residues 338-341 in TM6. Specifically, cysteines introduced cytoplasmic to the narrow region (i.e., positions 344 in TM6 and 1148 in TM12) can be modified by intracellular [Au(CN)2](-) in both open and closed states, corroborating the conclusion that the internal vestibule does not harbor a gate. However, cysteines engineered to positions external to the presumed narrow region (e.g., 334, 335, and 337 in TM6) are all nonreactive toward cytoplasmic [Au(CN)2](-) in the absence of ATP, whereas they can be better accessed by extracellular [Au(CN)2](-) when the open probability is markedly reduced by introducing a second mutation, G1349D. As [Au(CN)2](-) and chloride ions share the same permeation pathway, these results imply a gate is situated between amino acid residues 337 and 344 along TM6, encompassing the very segment that may also serve as the selectivity filter for CFTR. The unique position of a gate in the middle of the ion translocation pathway diverges from those seen in ATP-binding cassette (ABC) transporters and thus distinguishes CFTR from other members of the ABC transporter family.

  10. Reading Gate Positions with a Smartphone

    NASA Astrophysics Data System (ADS)

    van Overloop, Peter-Jules; Hut, Rolf

    2015-04-01

    Worldwide many flow gates are built in water networks in order to direct water to appropriate locations. Most of these gates are adjusted manually by field operators of water management organizations and it is often centrally not known what the new position of the gate is. This makes centralized management of the entire water network difficult. One of the reasons why the measurement of the gate position is usually not executed, is that for certain gates it is not easy to do such a reading. Tilting weirs or radial gates are examples where operators need special equipment (measuring rod and long level) to determine the position and it could even be a risky procedure. Another issue is that once the measurement is done, the value is jotted down in a notebook and later, at the office, entered in a computer system. So the entire monitoring procedure is not real-time and prone to human errors. A new way of monitoring gate positions is introduced. It consists of a level that is attached to the gate and an app with which a picture can be taken from the level. Using dedicated pattern recognition algorithms, the gate position can be read by using the angle of the level versus reference points on the gate, the radius of that gate and the absolute level of the joint around which the gate turn. The method uses gps-localization of the smartphone to store the gate position in the right location in the central database.

  11. HELLS GATE ROADLESS AREA, ARIZONA.

    USGS Publications Warehouse

    Conway, Clay M.; McColly, Robert A.

    1984-01-01

    Although no mineral-resource potential was identified in the Hells Gate Roadless Area during mineral surveys, the area is largely underlain by a regionally extensive Proterozoic granite-rhyolite complex which is tin-bearing. The geologic setting precludes the occurrence of fossil fuel resources and no other energy resources were identified. The potential for tin and associated metals in the Hells Gate Roadless Area and the region cannot be fully evaluated at this point. The granophyre and the upper part of the granite pluton along the northwestern margin of the area should be explored.

  12. Gating mechanisms of voltage-gated proton channels.

    PubMed

    Okamura, Yasushi; Fujiwara, Yuichiro; Sakata, Souhei

    2015-01-01

    Hv1 is a voltage-gated proton-selective channel that plays critical parts in host defense, sperm motility, and cancer progression. Hv1 contains a conserved voltage-sensor domain (VSD) that is shared by a large family of voltage-gated ion channels, but it lacks a pore domain. Voltage sensitivity and proton conductivity are conferred by a unitary VSD that consists of four transmembrane helices. The architecture of Hv1 differs from that of cation channels that form a pore in the center among multiple subunits (as in most cation channels) or homologous repeats (as in voltage-gated sodium and calcium channels). Hv1 forms a dimer in which a cytoplasmic coiled coil underpins the two protomers and forms a single, long helix that is contiguous with S4, the transmembrane voltage-sensing segment. The closed-state structure of Hv1 was recently solved using X-ray crystallography. In this article, we discuss the gating mechanism of Hv1 and focus on cooperativity within dimers and their sensitivity to metal ions.

  13. Radial gate evaluation: Olympus Dam, Colorado

    SciTech Connect

    1997-06-01

    The report presents a structural analysis of the radial gates of Olympus Dam in eastern Colorado. Five 20-foot wide by 17-foot high radial gates are used to control flow through the spillway at Olympus Dam. The spillway gates were designed in 1947. The gate arm assemblies consist of two separate wide flange beams, with a single brace between the arms. The arms pivot about a 4.0-inch diameter pin and bronze graphite-insert bushing. The pin is cantilevered from the pier anchor girder. The radial gates are supported by a pin bearing on a pier anchor birder bolted to the end of the concrete pier. The gates are operated by two-part wire rope 15,000-pound capacity hoise. Stoplog slots upstream of the radial gates are provided in the concrete piers. Selected drawings of the gates and hoists are located in appendix A.

  14. Chirality dependence of nanoscale ferromagnetic NOT gates

    NASA Astrophysics Data System (ADS)

    Lewis, E. R.; Petit, D.; O'Brien, L.; Zeng, H. T.; Read, D. E.; Cowburn, R. P.

    2011-03-01

    The behavior of a transverse domain wall (DW) interacting with a ferromagnetic NOT gate is studied with specific emphasis on the role of the DW chirality (sense of rotation of magnetization crossing the DW). We examine both the effect of the incoming DW chirality on the operation of the NOT gate and the effect of the gate on the DW chirality. We find that the chirality of the incoming DW does not affect the range of fields over which the NOT gate operates correctly. The effect of the NOT gate on the DW chirality depends on the chirality of the incoming DW: when the DW is incident on the NOT gate with the wide side of the DW on the inside of the V-shape formed by the gate, the chirality is conserved, but when the DW is incident on the gate with its wide side on the outside of the V-shape, the chirality may reverse.

  15. Talking with Microsoft's Bill Gates.

    ERIC Educational Resources Information Center

    EDUCOM Review, 1994

    1994-01-01

    Presents the transcript of an interview with William Gates, chairman of Microsoft Corporation. Topics discussed include continued support from the information technology industry for higher education; experiences with recent college graduates in the industry; new technologies developing in the near future; alliances in the computer industry; and…

  16. Double-disc gate valve

    DOEpatents

    Wheatley, Seth J.

    1979-01-01

    This invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewtih, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separtion of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve.

  17. Developing ICALL Tools Using GATE

    ERIC Educational Resources Information Center

    Wood, Peter

    2008-01-01

    This article discusses the use of the General Architecture for Text Engineering (GATE) as a tool for the development of ICALL and NLP applications. It outlines a paradigm shift in software development, which is mainly influenced by projects such as the Free Software Foundation. It looks at standards that have been proposed to facilitate the…

  18. Bill Gates eyes healthcare market.

    PubMed

    Dunbar, C

    1995-02-01

    The entrepreneurial spirit is still top in Bill Gates' mind as he look toward healthcare and other growth industries. Microsoft's CEO has not intention of going the way of other large technology companies that became obsolete before they could compete today.

  19. Developing ICALL Tools Using GATE

    ERIC Educational Resources Information Center

    Wood, Peter

    2008-01-01

    This article discusses the use of the General Architecture for Text Engineering (GATE) as a tool for the development of ICALL and NLP applications. It outlines a paradigm shift in software development, which is mainly influenced by projects such as the Free Software Foundation. It looks at standards that have been proposed to facilitate the…

  20. GATED PORES IN THE FERRITIN PROTEIN NANOCAGE

    PubMed Central

    Theil, Elizabeth C.; Liu, Xiaofeng S.; Tosha, Takehiko

    2008-01-01

    Synopsis and pictogram: Gated pores in the ferritin family of protein nanocages, illustrated in the pictogram, control transfer of ferrous iron into and out of the cages by regulating contact between hydrated ferric oxide mineral inside the protein cage, and reductants such as FMNH2 on the outside. The structural and functional homology between the gated ion channel proteins in inaccessible membranes and gated ferritin pores in the stable, water soluble nanoprotein, make studies of ferritin pores models for gated pores in many ion channel proteins. Properties of ferritin gated pores, which control rates of FMNH2 reduction of ferric iron in hydrated oxide minerals inside the protein nanocage, are discussed in terms of the conserved pore gate residues (arginine 72-apspartate 122 and leucine 110-leucine 134), of pore sensitivity to heat at temperatures 30 °C below that of the nanocage itself, and of pore sensitivity to physiological changes in urea (1–10 mM). Conditions which alter ferritin pore structure/function in solution, coupled with the high evolutionary conservation of the pore gates, suggest the presence of molecular regulators in vivo that recognize the pore gates and hold them either closed or open, depending on biological iron need. The apparent homology between ferrous ion transport through gated pores in the ferritin nanocage and ion transport through gated pores in ion channel proteins embedded in cell membranes, make studies of water soluble ferritin and the pore gating folding/unfolding a useful model for other gated pores. PMID:19262678

  1. Quantum Circuit Synthesis using a New Quantum Logic Gate Library of NCV Quantum Gates

    NASA Astrophysics Data System (ADS)

    Li, Zhiqiang; Chen, Sai; Song, Xiaoyu; Perkowski, Marek; Chen, Hanwu; Zhu, Wei

    2017-04-01

    Since Controlled-Square-Root-of-NOT (CV, CV‡) gates are not permutative quantum gates, many existing methods cannot effectively synthesize optimal 3-qubit circuits directly using the NOT, CNOT, Controlled-Square-Root-of-NOT quantum gate library (NCV), and the key of effective methods is the mapping of NCV gates to four-valued quantum gates. Firstly, we use NCV gates to create the new quantum logic gate library, which can be directly used to get the solutions with smaller quantum costs efficiently. Further, we present a novel generic method which quickly and directly constructs this new optimal quantum logic gate library using CNOT and Controlled-Square-Root-of-NOT gates. Finally, we present several encouraging experiments using these new permutative gates, and give a careful analysis of the method, which introduces a new idea to quantum circuit synthesis.

  2. Quantum Circuit Synthesis using a New Quantum Logic Gate Library of NCV Quantum Gates

    NASA Astrophysics Data System (ADS)

    Li, Zhiqiang; Chen, Sai; Song, Xiaoyu; Perkowski, Marek; Chen, Hanwu; Zhu, Wei

    2016-12-01

    Since Controlled-Square-Root-of-NOT (CV, CV‡) gates are not permutative quantum gates, many existing methods cannot effectively synthesize optimal 3-qubit circuits directly using the NOT, CNOT, Controlled-Square-Root-of-NOT quantum gate library (NCV), and the key of effective methods is the mapping of NCV gates to four-valued quantum gates. Firstly, we use NCV gates to create the new quantum logic gate library, which can be directly used to get the solutions with smaller quantum costs efficiently. Further, we present a novel generic method which quickly and directly constructs this new optimal quantum logic gate library using CNOT and Controlled-Square-Root-of-NOT gates. Finally, we present several encouraging experiments using these new permutative gates, and give a careful analysis of the method, which introduces a new idea to quantum circuit synthesis.

  3. Optimization of side gate length and side gate voltage for sub-100-nm double-gate MOSFET

    NASA Astrophysics Data System (ADS)

    Kim, Jae-hong; Kim, Geun-ho; Ko, Suk-woong; Jung, Hak-kee

    2002-11-01

    In this paper, we have investigated double gate (DG) MOSFET structure, which has main gate (MG) and two side gates (SG). We know that optimum side gate voltage for each side gate length is about 2V in the main gate 50nm. Also, we know that optimum side gate length for each main gate length is 70nm above. DG MOSFET shows a small threshold voltage (Vth) roll-off. From the I-V characteristics, we obtained IDsat=510μA/μm at VMG=VDS=1.5V and VSG=3.0V for DG MOSFET with the main gate length of 50nm and the side gate length of 70nm. The subthreshold slope is 86mV/decade, transconductance is 111μA/V and DIBL (Drain Induced Barrier Lowering) is 51.3mV. Then, we have investigated the advantage of this structure for the application to multi-input NAND gate logic. Also, we have presented that TCAD simulator is suitable for device simulation.

  4. Environmental noise reduction for holonomic quantum gates

    SciTech Connect

    Parodi, Daniele; Zanghi, Nino; Sassetti, Maura; Solinas, Paolo

    2007-07-15

    We study the performance of holonomic quantum gates, driven by lasers, under the effect of a dissipative environment modeled as a thermal bath of oscillators. We show how to enhance the performance of the gates by a suitable choice of the loop in the manifold of the controllable parameters of the laser. For a simplified, albeit realistic model, we find the surprising result that for a long time evolution the performance of the gate (properly estimated in terms of average fidelity) increases. On the basis of this result, we compare holonomic gates with the so-called stimulated raman adiabatic passage (STIRAP) gates.

  5. RGB-NIR active gated imaging

    NASA Astrophysics Data System (ADS)

    Spooren, Nick; Geelen, Bert; Tack, Klaas; Lambrechts, Andy; Jayapala, Murali; Ginat, Ran; David, Yaara; Levi, Eyal; Grauer, Yoav

    2016-10-01

    This paper presents multispectral active gated imaging in relation to the transportation and security fields. Active gated imaging is based on a fast gated camera and pulsed illuminator, synchronized in the time domain to provide range based images. We have developed a multispectral pattern deposited on a gated CMOS Image Sensor (CIS) with a pulsed Near Infrared VCSEL module. This paper will cover the component-level description of the multispectral gated CIS including the camera and illuminator units. Furthermore, the design considerations and characterization results of the spectral filters are presented together with a newly developed image processing method.

  6. Attosecond Temporal Gating with Elliptically Polarized Light

    SciTech Connect

    Dudovich, N.; Smirnova, O.; Ivanov, M. Yu.; Villeneuve, D. M.; Corkum, P. B.; Levesque, J.; Zeidler, D.; Comtois, D.

    2006-12-22

    Temporal gating allows high accuracy time-resolved measurements of a broad range of ultrafast processes. By manipulating the interaction between an atom and an intense laser field, we extend gating into the nonlinear medium in which attosecond optical and electron pulses are generated. Our gate is an amplitude gate induced by ellipticity of the fundamental pulse. The gate modulates the spectrum of the high harmonic emission and we use the measured modulation to characterize the sub-laser-cycle dynamics of the recollision electron wave packet.

  7. Fast Gate: Subnanosecond Gate Detectors for Laser Radiography

    SciTech Connect

    Trebes, J.; Feit, M.; Hatchett, S.; Key, M.; Phillips, T.; Sefcik, J.; Snavely, R.; Weber, M.

    2000-02-25

    X-ray radiography is used as a principal diagnostic in a wide range of hydrodynamic tests relevant to the weapons program and also for basic materials and equation-of-state science studies. The quality of the x-ray radiograph can be significantly degraded by the scattering of x-rays within the object and by components of the test system itself. Elimination of these scattered x-rays from the recorded images can either substantially improve the image contrast and signal-to-noise or allow smaller, lower-cost x-ray sources to be used. The scattered x-rays could be minimized through the use of a much shorter-duration x-ray pulse and a fast, gated detector. The short duration x-ray pulse and the fast gated detector allow detection of only those x-rays which pass through the object being radiographed. X-rays which are the result of scattering have longer path lengths and take longer to reach the target. Most of these can be eliminated if the detector if gated off before they arrive at the detector. Until recently there were no sources of high energy x-rays (1-10 MeV) with short duration (sub 100 picosecond) pulses. Now the Petawatt Laser Facility (ref 1) at Lawrence Livermore National Laboratory has been able to produce 0.1 rads at 1 meter of MeV energy x-rays in 1-0 picoseconds. Efforts are underway to significantly increase this x-ray output. The combination of the existing short-duration, Petawatt-produced x-ray pulses and an x-ray detector with sub-100-ps gate times could eliminate most of the scattered x-rays from the radiograph image and allow highly improved radiography particularly for larger, high density test objects.

  8. Unifying Gate Synthesis and Magic State Distillation

    NASA Astrophysics Data System (ADS)

    Campbell, Earl T.; Howard, Mark

    2017-02-01

    The leading paradigm for performing a computation on quantum memories can be encapsulated as distill-then-synthesize. Initially, one performs several rounds of distillation to create high-fidelity magic states that provide one good T gate, an essential quantum logic gate. Subsequently, gate synthesis intersperses many T gates with Clifford gates to realize a desired circuit. We introduce a unified framework that implements one round of distillation and multiquibit gate synthesis in a single step. Typically, our method uses the same number of T gates as conventional synthesis but with the added benefit of quadratic error suppression. Because of this, one less round of magic state distillation needs to be performed, leading to significant resource savings.

  9. Microscale Digital Vacuum Electronic Gates

    NASA Technical Reports Server (NTRS)

    Manohara, Harish (Inventor); Mojarradi, Mohammed M. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.

  10. Voltage-Gated Hydrophobic Nanopores

    SciTech Connect

    Lavrik, Nickolay V

    2011-01-01

    Hydrophobicity is a fundamental property that is responsible for numerous physical and biophysical aspects of molecular interactions in water. Peculiar behavior is expected for water in the vicinity of hydrophobic structures, such as nanopores. Indeed, hydrophobic nanopores can be found in two distinct states, dry and wet, even though the latter is thermodynamically unstable. Transitions between these two states are kinetically hindered in long pores but can be much faster in shorter pores. As it is demonstrated for the first time in this paper, these transitions can be induced by applying a voltage across a membrane with a single hydrophobic nanopore. Such voltage-induced gating in single nanopores can be realized in a reversible manner through electrowetting of inner walls of the nanopores. The resulting I-V curves of such artificial hydrophobic nanopores mimic biological voltage-gated channels.

  11. Cyclic networks of quantum gates

    NASA Astrophysics Data System (ADS)

    Cabauy, Peter

    In this thesis we first give an introduction to the basic aspects of quantum computation followed by an analysis of networks of quantum logic gates where the qubit lines are loops (cyclic). Thus far, investigations into cyclic networks of quantum logic gates have not been examined (as far as we know) by the quantum information community. In our investigations of cyclic quantum networks we have studied simple, one and two qubit systems. The analysis includes: classifying networks into groups, the dynamics of the qubits in a cyclic quantum network, and the perturbation effects of an external qubit acting on a cyclic quantum network. The analysis will be followed by a discussion on quantum algorithms and quantum information processing with cyclic quantum networks, a novel implementation of a cyclic network quantum memory and a discussion of quantum sensors via cyclic quantum networks.

  12. Improved Flux-Gate Magnetometer

    NASA Technical Reports Server (NTRS)

    Garner, H. Douglas

    1987-01-01

    Simplified circuit drives heading indicator and senses magnetic field of Earth. Simple flux-gate magnetometer supplies digital readout of magnetic heading of vehicle, developed to drive heading indicator, or supply heading information to autopilot or to other navigational instruments. Important feature is core driven into saturation in one direction only by alternating drive voltage, which swings from zero to one polarity and back. Made in part of commercially available integrated circuits.

  13. Gated high speed optical detector

    NASA Technical Reports Server (NTRS)

    Green, S. I.; Carson, L. M.; Neal, G. W.

    1973-01-01

    The design, fabrication, and test of two gated, high speed optical detectors for use in high speed digital laser communication links are discussed. The optical detectors used a dynamic crossed field photomultiplier and electronics including dc bias and RF drive circuits, automatic remote synchronization circuits, automatic gain control circuits, and threshold detection circuits. The equipment is used to detect binary encoded signals from a mode locked neodynium laser.

  14. Voltage-gated Proton Channels

    PubMed Central

    DeCoursey, Thomas E.

    2014-01-01

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

  15. Modes of glutamate receptor gating

    PubMed Central

    Popescu, Gabriela K

    2012-01-01

    Abstract The time course of excitatory synaptic currents, the major means of fast communication between neurons of the central nervous system, is encoded in the dynamic behaviour of post-synaptic glutamate-activated channels. First-pass attempts to explain the glutamate-elicited currents with mathematical models produced reaction mechanisms that included only the most basic functionally defined states: resting vs. liganded, closed vs. open, responsive vs. desensitized. In contrast, single-molecule observations afforded by the patch-clamp technique revealed an unanticipated kinetic multiplicity of transitions: from microseconds-lasting flickers to minutes-long modes. How these kinetically defined events impact the shape of the synaptic response, how they relate to rearrangements in receptor structure, and whether and how they are physiologically controlled represent currently active research directions. Modal gating, which refers to the slowest, least frequently observed ion-channel transitions, has been demonstrated for representatives of all ion channel families. However, reaction schemes have been largely confined to the short- and medium-range time scales. For glutamate receptors as well, modal gating has only recently come under rigorous scrutiny. This article reviews the evidence for modal gating of glutamate receptors and the still developing hypotheses about the mechanism(s) by which modal shifts occur and the ways in which they may impact the time course of synaptic transmission. PMID:22106181

  16. Monolithic transistor gate energy recovery system

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E. (Inventor)

    1989-01-01

    Energy is recovered from an insulated gate semiconductor switch, such as a MOSFET, that is otherwise lost in the gate capacitance by producing a notch in the gate control voltage for an interval B following an interval A after initial application of a gate control voltage pulse for turning the switch on, and a notch for an interval C following termination of the gate control voltage pulse followed by interval D during which the switch is turned on again, where each interval is a period .DELTA.T given by ##EQU1## L.sub.s is the inductance (discrete and/or parasitic) in series with the gate electrode of the insulated gate semiconductor switch, and C.sub.in is the capacitance of that switch between its gate and source electrodes. The interval .DELTA.T may be provided directly by timing in a pulse forming circuit for the gate control voltage applied, or adaptively by sensing the gate voltage v.sub.g and comparing it with fixed progressively higher voltages v.sub.1, v.sub.2 and v.sub.3, where v.sub.2 is intermediate v.sub.1 and v.sub.3 which correspond to the lower and upper levels of v.sub.g as the switch is turned off and on.

  17. Efficient Z gates for quantum computing

    NASA Astrophysics Data System (ADS)

    McKay, David C.; Wood, Christopher J.; Sheldon, Sarah; Chow, Jerry M.; Gambetta, Jay M.

    2017-08-01

    For superconducting qubits, microwave pulses drive rotations around the Bloch sphere. The phase of these drives can be used to generate zero-duration arbitrary virtual Z gates, which, combined with two Xπ /2 gates, can generate any SU(2) gate. Here we show how to best utilize these virtual Z gates to both improve algorithms and correct pulse errors. We perform randomized benchmarking using a Clifford set of Hadamard and Z gates and show that the error per Clifford is reduced versus a set consisting of standard finite-duration X and Y gates. Z gates can correct unitary rotation errors for weakly anharmonic qubits as an alternative to pulse-shaping techniques such as derivative removal by adiabatic gate (DRAG). We investigate leakage and show that a combination of DRAG pulse shaping to minimize leakage and Z gates to correct rotation errors realizes a 13.3 ns Xπ /2 gate characterized by low error [1.95 (3 ) ×10-4] and low leakage [3.1 (6 ) ×10-6] . Ultimately leakage is limited by the finite temperature of the qubit, but this limit is two orders of magnitude smaller than pulse errors due to decoherence.

  18. Gating of two pore domain potassium channels

    PubMed Central

    Mathie, Alistair; Al-Moubarak, Ehab; Veale, Emma L

    2010-01-01

    Two-pore-domain potassium (K2P) channels are responsible for background leak currents which regulate the membrane potential and excitability of many cell types. Their activity is modulated by a variety of chemical and physical stimuli which act to increase or decrease the open probability of individual K2P channels. Crystallographic data and homology modelling suggest that all K+ channels possess a highly conserved structure for ion selectivity and gating mechanisms. Like other K+ channels, K2P channels are thought to have two primary conserved gating mechanisms: an inactivation (or C-type) gate at the selectivity filter close to the extracellular side of the channel and an activation gate at the intracellular entrance to the channel involving key, identified, hinge glycine residues. Zinc and hydrogen ions regulate Drosophila KCNK0 and mammalian TASK channels, respectively, by interacting with the inactivation gate of these channels. In contrast, the voltage dependence of TASK3 channels is mediated through its activation gate. For KCNK0 it has been shown that the gates display positive cooperativity. It is of much interest to determine whether other K2P regulatory compounds interact with either the activation gate or the inactivation gate to alter channel activity or, indeed, whether additional regulatory gating pathways exist. PMID:20566661

  19. Gating of two pore domain potassium channels.

    PubMed

    Mathie, Alistair; Al-Moubarak, Ehab; Veale, Emma L

    2010-09-01

    Two-pore-domain potassium (K2P) channels are responsible for background leak currents which regulate the membrane potential and excitability of many cell types. Their activity is modulated by a variety of chemical and physical stimuli which act to increase or decrease the open probability of individual K2P channels. Crystallographic data and homology modelling suggest that all K(+) channels possess a highly conserved structure for ion selectivity and gating mechanisms. Like other K(+) channels, K2P channels are thought to have two primary conserved gating mechanisms: an inactivation (or C-type) gate at the selectivity filter close to the extracellular side of the channel and an activation gate at the intracellular entrance to the channel involving key, identified, hinge glycine residues. Zinc and hydrogen ions regulate Drosophila KCNK0 and mammalian TASK channels, respectively, by interacting with the inactivation gate of these channels. In contrast, the voltage dependence of TASK3 channels is mediated through its activation gate. For KCNK0 it has been shown that the gates display positive cooperativity. It is of much interest to determine whether other K2P regulatory compounds interact with either the activation gate or the inactivation gate to alter channel activity or, indeed, whether additional regulatory gating pathways exist.

  20. Hafnium zirconate gate dielectric for advanced gate stack applications

    NASA Astrophysics Data System (ADS)

    Hegde, R. I.; Triyoso, D. H.; Samavedam, S. B.; White, B. E.

    2007-04-01

    We report on the development of a hafnium zirconate (HfZrO4) alloy gate dielectric for advanced gate stack applications. The HfZrO4 and hafnium dioxide (HfO2) films were formed by atomic layer deposition using metal halides and heavy water as precursors. The HfZrO4 material properties were examined and compared with those of HfO2 by a wide variety of analytical methods. The dielectric properties, device performance, and reliability of HfZrO4 were investigated by fabricating HfZrO4/tantalum carbide (TaxCy) metal-oxide-semiconductor field effect transistor. The HfZrO4 dielectric film has smaller band gap, smaller and more uniform grains, less charge traps, and more uniform film quality than HfO2. The HfZrO4 dielectric films exhibited good thermal stability with silicon. Compared to HfO2, the HfZrO4 gate dielectric showed lower capacitance equivalent thickness value, higher transconductance, less charge trapping, higher drive current, lower threshold voltage (Vt), reduced capacitance-voltage (C-V ) hysteresis, lower interface state density, superior wafer level thickness uniformity, and longer positive bias temperature instability lifetime. Incorporation of zirconium dioxide (ZrO2) into HfO2 enhances the dielectric constant (k ) of the resulting HfZrO4 which is associated with structural phase transformation from mainly monoclinic to tetragonal. The tetragonal phase increases the k value of HfZrO4 dielectric to a large value as predicted. The improved device characteristics are attributed to less oxygen vacancy in the fine grained microstructure of HfZrO4 films.

  1. Reversible logic gate using adiabatic superconducting devices

    PubMed Central

    Takeuchi, N.; Yamanashi, Y.; Yoshikawa, N.

    2014-01-01

    Reversible computing has been studied since Rolf Landauer advanced the argument that has come to be known as Landauer's principle. This principle states that there is no minimum energy dissipation for logic operations in reversible computing, because it is not accompanied by reductions in information entropy. However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic devices. Another difficulty is that reversible logic gates must be both logically and physically reversible. Here we propose the first practical reversible logic gate using adiabatic superconducting devices and experimentally demonstrate the logical and physical reversibility of the gate. Additionally, we estimate the energy dissipation of the gate, and discuss the minimum energy dissipation required for reversible logic operations. It is expected that the results of this study will enable reversible computing to move from the theoretical stage into practical usage. PMID:25220698

  2. Reversible logic gate using adiabatic superconducting devices

    NASA Astrophysics Data System (ADS)

    Takeuchi, N.; Yamanashi, Y.; Yoshikawa, N.

    2014-09-01

    Reversible computing has been studied since Rolf Landauer advanced the argument that has come to be known as Landauer's principle. This principle states that there is no minimum energy dissipation for logic operations in reversible computing, because it is not accompanied by reductions in information entropy. However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic devices. Another difficulty is that reversible logic gates must be both logically and physically reversible. Here we propose the first practical reversible logic gate using adiabatic superconducting devices and experimentally demonstrate the logical and physical reversibility of the gate. Additionally, we estimate the energy dissipation of the gate, and discuss the minimum energy dissipation required for reversible logic operations. It is expected that the results of this study will enable reversible computing to move from the theoretical stage into practical usage.

  3. Reversible logic gate using adiabatic superconducting devices.

    PubMed

    Takeuchi, N; Yamanashi, Y; Yoshikawa, N

    2014-09-15

    Reversible computing has been studied since Rolf Landauer advanced the argument that has come to be known as Landauer's principle. This principle states that there is no minimum energy dissipation for logic operations in reversible computing, because it is not accompanied by reductions in information entropy. However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic devices. Another difficulty is that reversible logic gates must be both logically and physically reversible. Here we propose the first practical reversible logic gate using adiabatic superconducting devices and experimentally demonstrate the logical and physical reversibility of the gate. Additionally, we estimate the energy dissipation of the gate, and discuss the minimum energy dissipation required for reversible logic operations. It is expected that the results of this study will enable reversible computing to move from the theoretical stage into practical usage.

  4. A bistable electromagnetically actuated rotary gate microvalve

    NASA Astrophysics Data System (ADS)

    Luharuka, Rajesh; Hesketh, Peter J.

    2008-03-01

    Two types of rotary gate microvalves are developed for flow modulation in microfluidic systems. These microvalves have been tested for an open flow rate of up to 100 sccm and operate under a differential pressure of 6 psig with flow modulation of up to 100. The microvalve consists of a suspended gate that rotates in the plane of the chip to regulate flow through the orifice. The gate is suspended by a novel fully compliant in-plane rotary bistable micromechanism (IPRBM) that advantageously constrains the gate in all degrees of freedom except for in-plane rotational motion. Multiple inlet/outlet orifices provide flexibility of operating the microvalve in three different flow configurations. The rotary gate microvalve is switched with an external electromagnetic actuator. The suspended gate is made of a soft magnetic material and its electromagnetic actuation is based on the operating principle of a variable-reluctance stepper motor.

  5. Experimental superposition of orders of quantum gates

    PubMed Central

    Procopio, Lorenzo M.; Moqanaki, Amir; Araújo, Mateus; Costa, Fabio; Alonso Calafell, Irati; Dowd, Emma G.; Hamel, Deny R.; Rozema, Lee A.; Brukner, Časlav; Walther, Philip

    2015-01-01

    Quantum computers achieve a speed-up by placing quantum bits (qubits) in superpositions of different states. However, it has recently been appreciated that quantum mechanics also allows one to ‘superimpose different operations'. Furthermore, it has been shown that using a qubit to coherently control the gate order allows one to accomplish a task—determining if two gates commute or anti-commute—with fewer gate uses than any known quantum algorithm. Here we experimentally demonstrate this advantage, in a photonic context, using a second qubit to control the order in which two gates are applied to a first qubit. We create the required superposition of gate orders by using additional degrees of freedom of the photons encoding our qubits. The new resource we exploit can be interpreted as a superposition of causal orders, and could allow quantum algorithms to be implemented with an efficiency unlikely to be achieved on a fixed-gate-order quantum computer. PMID:26250107

  6. Experimental superposition of orders of quantum gates.

    PubMed

    Procopio, Lorenzo M; Moqanaki, Amir; Araújo, Mateus; Costa, Fabio; Alonso Calafell, Irati; Dowd, Emma G; Hamel, Deny R; Rozema, Lee A; Brukner, Časlav; Walther, Philip

    2015-08-07

    Quantum computers achieve a speed-up by placing quantum bits (qubits) in superpositions of different states. However, it has recently been appreciated that quantum mechanics also allows one to 'superimpose different operations'. Furthermore, it has been shown that using a qubit to coherently control the gate order allows one to accomplish a task--determining if two gates commute or anti-commute--with fewer gate uses than any known quantum algorithm. Here we experimentally demonstrate this advantage, in a photonic context, using a second qubit to control the order in which two gates are applied to a first qubit. We create the required superposition of gate orders by using additional degrees of freedom of the photons encoding our qubits. The new resource we exploit can be interpreted as a superposition of causal orders, and could allow quantum algorithms to be implemented with an efficiency unlikely to be achieved on a fixed-gate-order quantum computer.

  7. Contact gating at GHz frequency in graphene

    PubMed Central

    Wilmart, Q.; Inhofer, A.; Boukhicha, M.; Yang, W.; Rosticher, M.; Morfin, P.; Garroum, N.; Fève, G.; Berroir, J.-M.; Plaçais, B.

    2016-01-01

    The paradigm of graphene transistors is based on the gate modulation of the channel carrier density by means of a local channel gate. This standard architecture is subject to the scaling limit of the channel length and further restrictions due to access and contact resistances impeding the device performance. We propose a novel design, overcoming these issues by implementing additional local gates underneath the contact region which allow a full control of the Klein barrier taking place at the contact edge. In particular, our work demonstrates the GHz operation of transistors driven by independent contact gates. We benchmark the standard channel and novel contact gating and report for the later dynamical transconductance levels at the state of the art. Our finding may find applications in electronics and optoelectronics whenever there is need to control independently the Fermi level and the electrostatic potential of electronic sources or to get rid of cumbersome local channel gates. PMID:26879709

  8. System and Method for Scan Range Gating

    NASA Technical Reports Server (NTRS)

    Zuk, David M. (Inventor); Lindemann, Scott (Inventor)

    2017-01-01

    A system for scanning light to define a range gated signal includes a pulsed coherent light source that directs light into the atmosphere, a light gathering instrument that receives the light modified by atmospheric backscatter and transfers the light onto an image plane, a scanner that scans collimated light from the image plane to form a range gated signal from the light modified by atmospheric backscatter, a control circuit that coordinates timing of a scan rate of the scanner and a pulse rate of the pulsed coherent light source so that the range gated signal is formed according to a desired range gate, an optical device onto which an image of the range gated signal is scanned, and an interferometer to which the image of the range gated signal is directed by the optical device. The interferometer is configured to modify the image according to a desired analysis.

  9. Cognitive mechanisms associated with auditory sensory gating.

    PubMed

    Jones, L A; Hills, P J; Dick, K M; Jones, S P; Bright, P

    2016-02-01

    Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification.

  10. Contact gating at GHz frequency in graphene.

    PubMed

    Wilmart, Q; Inhofer, A; Boukhicha, M; Yang, W; Rosticher, M; Morfin, P; Garroum, N; Fève, G; Berroir, J-M; Plaçais, B

    2016-02-16

    The paradigm of graphene transistors is based on the gate modulation of the channel carrier density by means of a local channel gate. This standard architecture is subject to the scaling limit of the channel length and further restrictions due to access and contact resistances impeding the device performance. We propose a novel design, overcoming these issues by implementing additional local gates underneath the contact region which allow a full control of the Klein barrier taking place at the contact edge. In particular, our work demonstrates the GHz operation of transistors driven by independent contact gates. We benchmark the standard channel and novel contact gating and report for the later dynamical transconductance levels at the state of the art. Our finding may find applications in electronics and optoelectronics whenever there is need to control independently the Fermi level and the electrostatic potential of electronic sources or to get rid of cumbersome local channel gates.

  11. Cognitive mechanisms associated with auditory sensory gating

    PubMed Central

    Jones, L.A.; Hills, P.J.; Dick, K.M.; Jones, S.P.; Bright, P.

    2016-01-01

    Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification. PMID:26716891

  12. Criteria for universality of quantum gates

    NASA Astrophysics Data System (ADS)

    Sawicki, Adam; Karnas, Katarzyna

    2017-06-01

    We consider the problem of deciding if a set of quantum one-qudit gates S ={U1,...,Un} is universal. We provide the compact-form criteria leading to a simple algorithm that allows deciding the universality of any given set of gates in a finite number of steps. Moreover, for a nonuniversal S our criteria indicate what types of gates can be added to S to turn it into a universal set.

  13. Floating gate transistors as biosensors (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Frisbie, C. Daniel

    2016-11-01

    Electrolyte gated transistors (EGTs) are a sub-class of thin film transistors that are extremely promising for biological sensing applications. These devices employ a solid electrolyte as the gate insulator; the very large capacitance of the electrolyte results in low voltage operation and high transconductance or gain. This talk will describe the fabrication of floating gate EGTs and their use as ricin sensors. The critical performance metrics for EGTs compared with other types of TFTs will also be reviewed.

  14. Gate engineered performance of single molecular transistor

    NASA Astrophysics Data System (ADS)

    Ray, S. J.

    2016-05-01

    The operation, performance and electrostatics of multigated Single Molecular Transistor (SMT) devices are investigated using first-principles based density functional theory calculations for planar (pentacene) and non-planar (sucrose) molecules as islands. It has been found that the incorporation of larger numbers of gates allows enhanced electrostatic control in the SMT operation which has been quantified from the energy calculations and estimation of the gate capacitances. The effect of multiple gates is more dominant for a non-planar molecule than a planar molecule within an SMT which indicates the usefulness of such multi-gate architectures for future nanoelectronic devices.

  15. Realization of quantum gates by Lyapunov control

    NASA Astrophysics Data System (ADS)

    Hou, S. C.; Wang, L. C.; Yi, X. X.

    2014-02-01

    We propose a Lyapunov control design to achieve specific (or a family of) unitary time-evolution operators, i.e., quantum gates in the Schrödinger picture by tracking control. Two examples are presented. In the first, we illustrate how to realize the Hadamard gate in a single-qubit system, while in the second, the controlled-NOT (CNOT) gate is implemented in two-qubit systems with the Ising and Heisenberg interactions. Furthermore, we demonstrate that the control can drive the time-evolution operator into the local equivalence class of the CNOT gate and the operator keeps in this class forever with the existence of Ising coupling.

  16. Four Great Gates: Dilemmas, Directions and Distractions in Educational Research

    ERIC Educational Resources Information Center

    Delamont, Sara

    2005-01-01

    In James Elroy Flecker's poem "The Gates of Damascus", the poet imagines four exits from the safe comfortable city to the outside world. Each gate takes the traveller into a different set of temptations and dangers. The Aleppo Gate leads to trade and commerce, the Mecca Gate is for faith and pilgrimage, the Lebanon Gate is for exploration and the…

  17. Gating, enhanced gating, and beyond: information utilization strategies for motion management, applied to preclinical PET

    PubMed Central

    2013-01-01

    Background Respiratory gating and gate optimization strategies present solutions for overcoming image degradation caused by respiratory motion in PET and traditionally utilize hardware systems and/or employ complex processing algorithms. In this work, we aimed to advance recently emerging data-driven gating methods and introduce a new strategy for optimizing the four-dimensional data based on information contained in that data. These algorithms are combined to form an automated motion correction workflow. Methods Software-based gating methods were applied to a nonspecific population of 84 small-animal rat PET scans to create respiratory gated images. The gated PET images were then optimized using an algorithm we introduce as ‘gating+’ to reduce noise and optimize signal; the technique was also tested using simulations. Gating+ is based on a principle of only using gated information if and where it adds a net benefit, as evaluated in temporal frequency space. Motion-corrected images were assessed quantitatively and qualitatively. Results Of the small-animal PET scans, 71% exhibited quantifiable motion after software gating. The mean liver displacement was 3.25 mm for gated and 3.04 mm for gating+ images. The (relative) mean percent standard deviations measured in background ROIs were 1.53, 1.05, and 1.00 for the gated, gating+, and ungated values, respectively. Simulations confirmed that gating+ image voxels had a higher probability of being accurate relative to the corresponding ungated values under varying noise and motion scenarios. Additionally, we found motion mapping and phase decoupling models that readily extend from gating+ processing. Conclusions Raw PET data contain information about motion that is not currently utilized. In our work, we showed that through automated processing of standard (ungated) PET acquisitions, (motion-) information-rich images can be constructed with minimal risk of noise introduction. Such methods have the potential for

  18. Picosecond Optoelectronic AND-GATE

    DTIC Science & Technology

    1994-08-01

    SOTA. The bias, gate. and 13 ground probes make contact to their respective bond pads. Fig. 12 Temporal response of the SOTA. 14 Fig. 13 Sheet resistance for...post-annealed, lattice matched LT-GaAs, LT- 18 In0.35GaO. 65 As, LT-In0.53Ga0 .4 7As. The sheet resistance for polycrystalline LT-In0 .35Ga0...65As is also shown. The minimum acceptable values for sheet resistance for detector areas of 50x50 ptm 2 and 8x8 4tm 2 are shown and correspond to a dark

  19. Voltage-Gated Calcium Channels

    NASA Astrophysics Data System (ADS)

    Zamponi, Gerald Werner

    Voltage Gated Calcium Channels is the first comprehensive book in the calcium channel field, encompassing over thirty years of progress towards our understanding of calcium channel structure, function, regulation, physiology, pharmacology, and genetics. This book balances contributions from many of the leading authorities in the calcium channel field with fresh perspectives from risings stars in the area, taking into account the most recent literature and concepts. This is the only all-encompassing calcium channel book currently available, and is an essential resource for academic researchers at all levels in the areas neuroscience, biophysics, and cardiovascular sciences, as well as to researchers in the drug discovery area.

  20. Stimuli-responsive smart gating membranes.

    PubMed

    Liu, Zhuang; Wang, Wei; Xie, Rui; Ju, Xiao-Jie; Chu, Liang-Yin

    2016-02-07

    Membranes are playing paramount roles in the sustainable development of myriad fields such as energy, environmental and resource management, and human health. However, the unalterable pore size and surface properties of traditional porous membranes restrict their efficient applications. The performances of traditional membranes will be weakened upon unavoidable membrane fouling, and they cannot be applied to cases where self-regulated permeability and selectivity are required. Inspired by natural cell membranes with stimuli-responsive channels, artificial stimuli-responsive smart gating membranes are developed by chemically/physically incorporating stimuli-responsive materials as functional gates into traditional porous membranes, to provide advanced functions and enhanced performances for breaking the bottlenecks of traditional membrane technologies. Smart gating membranes, integrating the advantages of traditional porous membrane substrates and smart functional gates, can self-regulate their permeability and selectivity via the flexible adjustment of pore sizes and surface properties based on the "open/close" switch of the smart gates in response to environmental stimuli. This tutorial review summarizes the recent developments in stimuli-responsive smart gating membranes, including the design strategies and the fabrication strategies that are based on the introduction of the stimuli-responsive gates after or during membrane formation, and the positively and negatively responsive gating models of versatile stimuli-responsive smart gating membranes, as well as the advanced applications of smart gating membranes for regulating substance concentration in reactors, controlling the release rate of drugs, separating active molecules based on size or affinity, and the self-cleaning of membrane surfaces. With self-regulated membrane performances, smart gating membranes show great power for use in global sustainable development.

  1. Hydrophobic Gating in Ion Channels

    PubMed Central

    Aryal, Prafulla; Sansom, Mark S.P.; Tucker, Stephen J.

    2016-01-01

    Biological ion channels are nanoscale transmembrane pores. When water and ions are enclosed within the narrow confines of a sub-nanometer hydrophobic pore, they exhibit behavior not evident from macroscopic descriptions. At this nanoscopic level, the unfavorable interaction between the lining of a hydrophobic pore and water may lead to liquid-vapor oscillations. The resultant transient vapor state is ‘dewetted’ i.e. effectively devoid of water molecules within all, or part of the pore, thus leading to an energetic barrier to ion conduction. This process, termed ‘hydrophobic gating’, was first observed in molecular dynamics simulations of model nanopores, where the principles underlying hydrophobic gating (i.e. changes in diameter, polarity, or transmembrane voltage) have now been extensively validated. Computational, structural and functional studies now indicate that biological ion channels may also exploit hydrophobic gating to regulate ion flow within their pores. Here we review the evidence for this process, and propose that this unusual behavior of water represents an increasingly important element in understanding the relationship between ion channel structure and function. PMID:25106689

  2. 23. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING TRUNNION PIN, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING TRUNNION PIN, GATE ARM AND GATE GAUGE, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  3. 17. DETAIL VIEW OF TAINTER GATE, SHOWING SUBMERSIBLE (LEFT) AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF TAINTER GATE, SHOWING SUBMERSIBLE (LEFT) AND NONSUBMERSIBLE (RIGHT) GATES, PIERS AND DAM BRIDGE, WITH ROLLER GATE HEADHOUSE IN BACKGROUND, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  4. 2. DETAIL OF CONTROL GATE ADJACENT TO LIFT LOCK NO. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. DETAIL OF CONTROL GATE ADJACENT TO LIFT LOCK NO. 7; THIS CONTROL GATE IS A 1980s RECONSTRUCTION. - Illinois & Michigan Canal, Lift Lock No. 7 & Control Gate, East side of DuPage River, Channahon, Will County, IL

  5. 17. DETAIL VIEW OF ROLLER GATE (IN RAISED POSITION), SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF ROLLER GATE (IN RAISED POSITION), SHOWING GATE FLANGES, GATE HEATER (LEFT FOREGROUND), ROLLER TRACK, CHAIN AND BRIDGE GIRDER, LOOKING EAST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 3, Red Wing, Goodhue County, MN

  6. Nanosecond gating properties of proximity focused microchannel plate image intensifiers

    NASA Astrophysics Data System (ADS)

    King, N. S. P.; King, N. S. P.; Yates, G. J.; Jaramillo, S. A.; Noel, B. W.; Detch, J. L., Jr.; Ogle, J. W.

    The optical gating properties of Multichannel plate image intensifiers were characterized. Emphasis was placed on parameters relevant to gating speed and correlations between the applied electrical and resultant optical gates.

  7. Terahertz amplification in RTD-gated HEMTs with a grating-gate wave coupling topology

    NASA Astrophysics Data System (ADS)

    Condori Quispe, Hugo O.; Encomendero-Risco, Jimy J.; Xing, Huili Grace; Sensale-Rodriguez, Berardi

    2016-08-01

    We theoretically analyze the operation of a terahertz amplifier consisting of a resonant-tunneling-diode gated high-electron-mobility transistor (RTD-gated HEMT) in a grating-gate topology. In these devices, the key element enabling substantial power gain is the efficient coupling of terahertz waves into and out of plasmons in the RTD-gated HEMT channel, i.e., the gain medium, via the grating-gate itself, part of the active device, rather than by an external antenna structure as discussed in previous works, therefore potentially enabling terahertz amplification with associated power gains >40 dB.

  8. A gate drive circuit for gate-turn-off (GTO) devices in series stack.

    SciTech Connect

    Despe, O.

    1999-04-13

    A gate-turn-off (GTO) switch is under development at the Advanced Photon Source as a replacement for a thyratron switch in high power pulsed application. The high voltage in the application requires multiple GTOs connected in series. One component that is critical to the success of GTO operation is the gate drive circuit. The gate drive circuit has to provide fast high-current pulses to the GTO gate for fast turn-on and turn-off. It also has to be able to operate while floating at high voltage. This paper describes a gate drive circuit that meets these requirements.

  9. Terahertz amplification in RTD-gated HEMTs with a grating-gate wave coupling topology

    SciTech Connect

    Condori Quispe, Hugo O.; Sensale-Rodriguez, Berardi; Encomendero-Risco, Jimy J.; Xing, Huili Grace

    2016-08-08

    We theoretically analyze the operation of a terahertz amplifier consisting of a resonant-tunneling-diode gated high-electron-mobility transistor (RTD-gated HEMT) in a grating-gate topology. In these devices, the key element enabling substantial power gain is the efficient coupling of terahertz waves into and out of plasmons in the RTD-gated HEMT channel, i.e., the gain medium, via the grating-gate itself, part of the active device, rather than by an external antenna structure as discussed in previous works, therefore potentially enabling terahertz amplification with associated power gains >40 dB.

  10. Protected gates for topological quantum field theories

    NASA Astrophysics Data System (ADS)

    Beverland, Michael E.; Buerschaper, Oliver; Koenig, Robert; Pastawski, Fernando; Preskill, John; Sijher, Sumit

    2016-02-01

    We study restrictions on locality-preserving unitary logical gates for topological quantum codes in two spatial dimensions. A locality-preserving operation is one which maps local operators to local operators — for example, a constant-depth quantum circuit of geometrically local gates, or evolution for a constant time governed by a geometrically local bounded-strength Hamiltonian. Locality-preserving logical gates of topological codes are intrinsically fault tolerant because spatially localized errors remain localized, and hence sufficiently dilute errors remain correctable. By invoking general properties of two-dimensional topological field theories, we find that the locality-preserving logical gates are severely limited for codes which admit non-abelian anyons, in particular, there are no locality-preserving logical gates on the torus or the sphere with M punctures if the braiding of anyons is computationally universal. Furthermore, for Ising anyons on the M-punctured sphere, locality-preserving gates must be elements of the logical Pauli group. We derive these results by relating logical gates of a topological code to automorphisms of the Verlinde algebra of the corresponding anyon model, and by requiring the logical gates to be compatible with basis changes in the logical Hilbert space arising from local F-moves and the mapping class group.

  11. Channel gating pore: a new therapeutic target.

    PubMed

    Kornilov, Polina; Peretz, Asher; Attali, Bernard

    2013-09-01

    Each subunit of voltage-gated cation channels comprises a voltage-sensing domain and a pore region. In a paper recently published in Cell Research, Li et al. showed that the gating charge pathway of the voltage sensor of the KCNQ2 K+ channel can accommodate small opener molecules and offer a new target to treat hyperexcitability disorders.

  12. Quantum logic gates for superconducting resonator qudits

    SciTech Connect

    Strauch, Frederick W.

    2011-11-15

    We study quantum information processing using superpositions of Fock states in superconducting resonators as quantum d-level systems (qudits). A universal set of single and coupled logic gates is theoretically proposed for resonators coupled by superconducting circuits of Josephson junctions. These gates use experimentally demonstrated interactions and provide an attractive route to quantum information processing using harmonic oscillator modes.

  13. Using Gates to Enhance Your Paddling Program.

    ERIC Educational Resources Information Center

    Kauffman, Robert B.; Mason, David W.

    1995-01-01

    Describes methods for constructing gates and slalom courses to teach paddling skills to young campers. Describes how the English Gate system, a standardized course, can be used both for instruction and to test camper's paddling skills. Recommends the use of a three-level award system (novice, intermediate, and expert) to recognize camper…

  14. Reconstruction of dynamic gated cardiac SPECT

    SciTech Connect

    Jin Mingwu; Yang Yongyi; King, Michael A.

    2006-11-15

    In this paper we propose an image reconstruction procedure which aims to unify gated single photon emission computed tomography (SPECT) and dynamic SPECT into a single method. We divide the cardiac cycle into a number of gate intervals as in gated SPECT, but treat the tracer distribution for each gate as a time-varying signal. By using both dynamic and motion-compensated temporal regularization, our reconstruction procedure will produce an image sequence that shows both cardiac motion and time-varying tracer distribution simultaneously. To demonstrate the proposed reconstruction method, we simulated gated cardiac perfusion imaging using the gated mathematical cardiac-torso (gMCAT) phantom with Tc99m-Teboroxime as the imaging agent. Our results show that the proposed method can produce more accurate reconstruction of gated dynamic images than independent reconstruction of individual gate frames with spatial smoothness alone. In particular, our results show that the former could improve the contrast to noise ratio of a simulated perfusion defect by as much as 100% when compared to the latter.

  15. Protected gates for topological quantum field theories

    SciTech Connect

    Beverland, Michael E.; Pastawski, Fernando; Preskill, John; Buerschaper, Oliver; Koenig, Robert; Sijher, Sumit

    2016-02-15

    We study restrictions on locality-preserving unitary logical gates for topological quantum codes in two spatial dimensions. A locality-preserving operation is one which maps local operators to local operators — for example, a constant-depth quantum circuit of geometrically local gates, or evolution for a constant time governed by a geometrically local bounded-strength Hamiltonian. Locality-preserving logical gates of topological codes are intrinsically fault tolerant because spatially localized errors remain localized, and hence sufficiently dilute errors remain correctable. By invoking general properties of two-dimensional topological field theories, we find that the locality-preserving logical gates are severely limited for codes which admit non-abelian anyons, in particular, there are no locality-preserving logical gates on the torus or the sphere with M punctures if the braiding of anyons is computationally universal. Furthermore, for Ising anyons on the M-punctured sphere, locality-preserving gates must be elements of the logical Pauli group. We derive these results by relating logical gates of a topological code to automorphisms of the Verlinde algebra of the corresponding anyon model, and by requiring the logical gates to be compatible with basis changes in the logical Hilbert space arising from local F-moves and the mapping class group.

  16. Retaining latch for a water pit gate

    DOEpatents

    Beale, A.R.

    1997-11-18

    A retaining latch is described for use in a hazardous materials storage or handling facility to adjustably retain a water pit gate in a gate frame. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame. 4 figs.

  17. Retaining latch for a water pit gate

    SciTech Connect

    Beale, A.R.

    1997-11-18

    A retaining latch is described for use in a hazardous materials storage or handling facility to adjustably retain a water pit gate in a gate frame. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame. 4 figs.

  18. Retaining latch for a water pit gate

    SciTech Connect

    Beale, A.R.

    1996-12-31

    The present invention relates to retaining devices which are used to latch two elements or parts together and, more particularly, to gate latches for use in locking a gate to a wall bracket in a water pit utilized to store or handle hazardous materials. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame.

  19. Retaining latch for a water pit gate

    SciTech Connect

    Beale, Arden R.

    1997-01-01

    A retaining latch for use in a hazardous materials storage or handling facility to adjustably retain a water pit gate in a gate frame. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame.

  20. Automatically closing swing gate closure assembly

    DOEpatents

    Chang, Shih-Chih; Schuck, William J.; Gilmore, Richard F.

    1988-01-01

    A swing gate closure assembly for nuclear reactor tipoff assembly wherein the swing gate is cammed open by a fuel element or spacer but is reliably closed at a desired closing rate primarily by hydraulic forces in the absence of a fuel charge.

  1. Terahertz plasmon amplification in RTD-gated HEMTs with a grating-gate

    NASA Astrophysics Data System (ADS)

    Condori Quispe, Hugo O.; Encomendero, Jimy; Xing, Huili Grace; Sensale Rodriguez, Berardi

    2016-09-01

    We analyze amplification of terahertz plasmons in a grating-gate semiconductor hetero-structure. The device consists of a resonant-tunneling-diode gated high-electron-mobility transistor (RTD-gated HEMT), i.e. a HEMT structure with a double-barrier gate stack enabling resonant tunneling from gate to channel. In these devices, the key element enabling substantial power gain is the coupling of terahertz waves into and out of plasmons in the RTD-gated HEMT channel, i.e. the gain medium, via the grating-gate itself, part of the active device, rather than by an external antenna structure as in previous works, enabling amplification with associated power gain >> 30 dB at room temperature.

  2. Dual-Gate p-GaN Gate High Electron Mobility Transistors for Steep Subthreshold Slope.

    PubMed

    Bae, Jong-Ho; Lee, Jong-Ho

    2016-05-01

    A steep subthreshold slope characteristic is achieved through p-GaN gate HEMT with dual-gate structure. Obtained subthreshold slope is less than 120 μV/dec. Based on the measured and simulated data obtained from single-gate device, breakdown of parasitic floating-base bipolar transistor and floating gate charged with holes are responsible to increase abruptly in drain current. In the dual-gate device, on-current degrades with high temperature but subthreshold slope is not changed. To observe the switching speed of dual-gate device and transient response of drain current are measured. According to the transient responses of drain current, switching speed of the dual-gate device is about 10(-5) sec.

  3. Gating of Permanent Molds for ALuminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  4. Logic gates based on ion transistors.

    PubMed

    Tybrandt, Klas; Forchheimer, Robert; Berggren, Magnus

    2012-05-29

    Precise control over processing, transport and delivery of ionic and molecular signals is of great importance in numerous fields of life sciences. Integrated circuits based on ion transistors would be one approach to route and dispense complex chemical signal patterns to achieve such control. To date several types of ion transistors have been reported; however, only individual devices have so far been presented and most of them are not functional at physiological salt concentrations. Here we report integrated chemical logic gates based on ion bipolar junction transistors. Inverters and NAND gates of both npn type and complementary type are demonstrated. We find that complementary ion gates have higher gain and lower power consumption, as compared with the single transistor-type gates, which imitates the advantages of complementary logics found in conventional electronics. Ion inverters and NAND gates lay the groundwork for further development of solid-state chemical delivery circuits.

  5. Glare suppression by coherence gated negation

    PubMed Central

    Zhou, Edward Haojiang; Shibukawa, Atsushi; Brake, Joshua; Ruan, Haowen; Yang, Changhuei

    2016-01-01

    Imaging of a weak target hidden behind a scattering medium can be significantly confounded by glare. We report a method, termed coherence gated negation (CGN), that uses destructive optical interference to suppress glare and allow improved imaging of a weak target. As a demonstration, we show that by permuting through a set range of amplitude and phase values for a reference beam interfering with the optical field from the glare and target reflection, we can suppress glare by an order of magnitude, even when the optical wavefront is highly disordered. This strategy significantly departs from conventional coherence gating methods in that CGN actively “gates out” the unwanted optical contributions while conventional methods “gate in” the target optical signal. We further show that the CGN method can outperform conventional coherence gating image quality in certain scenarios by more effectively rejecting unwanted optical contributions. PMID:28713849

  6. Characteristics of gated treatment using an optical surface imaging and gating system on an Elekta linac.

    PubMed

    Freislederer, Philipp; Reiner, Michael; Hoischen, Winfried; Quanz, Anton; Heinz, Christian; Walter, Franziska; Belka, Claus; Soehn, Matthias

    2015-03-19

    Knowing the technical characteristics of gated radiotherapy equipment is crucial for ensuring precise and accurate treatment when using techniques such as Deep-Inspiration Breath-Hold and gating under free breathing. With one of the first installations of the novel surface imaging system Catalyst™ (C-RAD AB, Sweden) in connection with an Elekta Synergy linear accelerator (Elekta AB, Sweden) via the Elekta Response Interface, characteristics like dose delivery accuracy and time delay were investigated prior to clinical implementation of gated treatments in our institution. In this study a moving phantom was used to simulate respiratory motion which was registered by the Catalyst™ system. The gating level was set manually. Within this gating window a trigger signal is automatically sent to the linac initiating treatment delivery. Dose measurements of gated linac treatment beams with different gating levels were recorded with a static 2D-Diode Array (MapCheck2, Sun Nuclear Co., USA) and compared to ungated reference measurements for different field sizes. In addition, the time delay of gated treatment beams was measured using radiographic film. The difference in dose delivery between gated and ungated treatment decreases with the size of the chosen gating level. For clinically relevant gating levels of about 30%, the differences in dose delivery accuracy remain below 1%. In comparison with other system configurations in literature, the beam-on time delay shows a large deviation of 851 ms ± 100 ms. When performing gated treatment, especially for free-breathing gating, factors as time delay and dose delivery have to be evaluated regularly in terms of a quality assurance process. Once these parameters are known they can be accounted and compensated for, e.g. by adjusting the pre-selected gating level or the internal target volume margins and by using prediction algorithms for breathing curves. The usage of prediction algorithms becomes inevitable with the high

  7. Gate Controlled Spin Precession Effect

    NASA Astrophysics Data System (ADS)

    Naser Zainuddin, Abu; Siddiqui, Lutfe; Hong, Seokmin; Datta, Supriyo

    2010-03-01

    A two-dimensional (2D) non-local lateral spin-transport model is developed based on the non-equilibrium Green's function (NEGF) formalism for ballistic carriers in mode space approach. The effect of gate controlled Rashba spin-orbit (RSO) interaction in modulating the non-local spin voltage has been explicitly taken into account. We found a quantitative agreement with the recent observation on non-local controlled spin-precession by Koo et. al [1]. The phase shift observed in the voltage according to the analytical equation used in [1] is found to be the consequence of both multichannel effect and the effect of injecting and detecting ferromagnetic contact length. In such structures we predict that a short length contact as well as an etched out channel can improve the non-local voltage significantly. [1] H. C. Koo et. al. Science, 325, 1515 (2009).

  8. Locking apparatus for gate valves

    DOEpatents

    Fabyan, J.; Williams, C.W.

    A locking apparatus for fluid operated valves having a piston connected to the valve actuator which moves in response to applied pressure within a cylinder housing having a cylinder head, a catch block is secured to the piston, and the cylinder head incorporates a catch pin. Pressure applied to the cylinder to open the valve moves the piston adjacent to the cylinder head where the catch pin automatically engages the catch block preventing further movement of the piston or premature closure of the valve. Application of pressure to the cylinder to close the valve, retracts the catch pin, allowing the valve to close. Included are one or more selector valves, for selecting pressure application to other apparatus depending on the gate valve position, open or closed, protecting such apparatus from damage due to premature closing caused by pressure loss or operational error.

  9. Locking apparatus for gate valves

    DOEpatents

    Fabyan, Joseph; Williams, Carl W.

    1988-01-01

    A locking apparatus for fluid operated valves having a piston connected to the valve actuator which moves in response to applied pressure within a cylinder housing having a cylinder head, a catch block is secured to the piston, and the cylinder head incorporates a catch pin. Pressure applied to the cylinder to open the valve moves the piston adjacent to the cylinder head where the catch pin automatically engages the catch block preventing futher movement of the piston or premature closure of the valve. Application of pressure to the cylinder to close the valve, retracts the catch pin, allowing the valve to close. Included are one or more selector valves, for selecting pressure application to other apparatus depending on the gate valve position, open or closed, protecting such apparatus from damage due to premature closing caused by pressure loss or operational error.

  10. Voltage-gated sodium channels

    PubMed Central

    Abdelsayed, Mena; Sokolov, Stanislav

    2013-01-01

    Epilepsy is a brain disorder characterized by seizures and convulsions. The basis of epilepsy is an increase in neuronal excitability that, in some cases, may be caused by functional defects in neuronal voltage gated sodium channels, Nav1.1 and Nav1.2. The effects of antiepileptic drugs (AEDs) as effective therapies for epilepsy have been characterized by extensive research. Most of the classic AEDs targeting Nav share a common mechanism of action by stabilizing the channel’s fast-inactivated state. In contrast, novel AEDs, such as lacosamide, stabilize the slow-inactivated state in neuronal Nav1.1 and Nav1.7 isoforms. This paper reviews the different mechanisms by which this stabilization occurs to determine new methods for treatment. PMID:23531742

  11. Mechanosensitive gating of Kv channels.

    PubMed

    Morris, Catherine E; Prikryl, Emil A; Joós, Béla

    2015-01-01

    K-selective voltage-gated channels (Kv) are multi-conformation bilayer-embedded proteins whose mechanosensitive (MS) Popen(V) implies that at least one conformational transition requires the restructuring of the channel-bilayer interface. Unlike Morris and colleagues, who attributed MS-Kv responses to a cooperative V-dependent closed-closed expansion↔compaction transition near the open state, Mackinnon and colleagues invoke expansion during a V-independent closed↔open transition. With increasing membrane tension, they suggest, the closed↔open equilibrium constant, L, can increase >100-fold, thereby taking steady-state Popen from 0→1; "exquisite sensitivity to small…mechanical perturbations", they state, makes a Kv "as much a mechanosensitive…as…a voltage-dependent channel". Devised to explain successive gK(V) curves in excised patches where tension spontaneously increased until lysis, their L-based model falters in part because of an overlooked IK feature; with recovery from slow inactivation factored in, their g(V) datasets are fully explained by the earlier model (a MS V-dependent closed-closed transition, invariant L≥4). An L-based MS-Kv predicts neither known Kv time courses nor the distinctive MS responses of Kv-ILT. It predicts Kv densities (hence gating charge per V-sensor) several-fold different from established values. If opening depended on elevated tension (L-based model), standard gK(V) operation would be compromised by animal cells' membrane flaccidity. A MS V-dependent transition is, by contrast, unproblematic on all counts. Since these issues bear directly on recent findings that mechanically-modulated Kv channels subtly tune pain-related excitability in peripheral mechanoreceptor neurons we undertook excitability modeling (evoked action potentials). Kvs with MS V-dependent closed-closed transitions produce nuanced mechanically-modulated excitability whereas an L-based MS-Kv yields extreme, possibly excessive (physiologically

  12. Range gating experiments through a scattering media

    SciTech Connect

    Payton, J.; Cverna, F.; Gallegos, R.; McDonald, T.; Numkena, D.; Obst, A.; Pena-Abeyta, C.; Yates, G.

    1998-12-31

    This paper discusses range-gated imaging experiments performed recently at Redstone Arsenal in Huntsville, Alabama. Range gating is an imaging technique that uses a pulsed laser and gated camera to image objects at specific ranges. The technique can be used for imaging through scattering media such as dense smoke or fog. Range gating uses the fact that light travels at 3 x 10{sup 8} m/s. Knowing the speed of light the authors can calculate the time it will take the laser light to travel a known distance, then gate open a Micro Channel Plate Image Intensifier (MCPII) at the time the reflected light returns from the target. In the Redstone experiment the gate width on the MCPII was set to equal the laser pulse width ({approximately} 8 ns) for the highest signal to noise ratio. The gate allows the light reflected form the target and a small portion of the light reflected from the smoke in the vicinity of the target to be imaged. They obtained good results in light and medium smoke but the laser they were used did not have sufficient intensity to penetrate the thickest smoke. They did not diverge the laser beam to cover the entire target in order to maintain a high flux that would achieve better penetration through the smoke. They were able to image an Armored Personnel Carrier (APC) through light and medium smoke but they were not able to image the APC through heavy smoke. The experiment and results are presented.

  13. Graduate Automotive Technology Education (GATE) Center

    SciTech Connect

    Jeffrey Hodgson; David Irick

    2005-09-30

    The Graduate Automotive Technology Education (GATE) Center at the University of Tennessee, Knoxville has completed its sixth year of operation. During this period the Center has involved thirteen GATE Fellows and ten GATE Research Assistants in preparing them to contribute to advanced automotive technologies in the center's focus area: hybrid drive trains and control systems. Eighteen GATE students have graduated, and three have completed their course work requirements. Nine faculty members from three departments in the College of Engineering have been involved in the GATE Center. In addition to the impact that the Center has had on the students and faculty involved, the presence of the center has led to the acquisition of resources that probably would not have been obtained if the GATE Center had not existed. Significant industry interaction such as internships, equipment donations, and support for GATE students has been realized. The value of the total resources brought to the university (including related research contracts) exceeds $4,000,000. Problem areas are discussed in the hope that future activities may benefit from the operation of the current program.

  14. Gated escaping of ligand out of protein

    NASA Astrophysics Data System (ADS)

    Sheu, Sheh-Yi; Yang, Dah-Yen

    2000-01-01

    We construct a new gating model and develop a new theory to study the escaping process of a ligand out of a spherical cavity with a puncture (or gate) on the surface. The gate undulation can be regulated by any time-dependent function and the motion of the ligand inside the spherical cavity is mapped into a two-dimensional entropy potential surface. Hence the driving force of our model is entropy only. For a static gate, the escaping process corresponds to climbing a two-dimensional entropy barrier. When the gate open angle is small, the escaping rate is proportional to the square of the opening angle. The prefactor of the escaping rate constant depends on the curvature of the entropy potential surface. For coherent gating, the survival time depends not only on the gate undulation frequency but also on how the initial state is defined. On the escaping from protein, our escaping rate shows it is qualitatively consistent with the experimental result of ligand recombination in myoglobin.

  15. Adaptive quantum gate-set tomography

    NASA Astrophysics Data System (ADS)

    Blume-Kohout, Robin

    2013-03-01

    Quantum information hardware needs to be characterized and calibrated. This is the job of quantum state and process tomography, but standard tomographic methods have an Achilles heel: to characterize an unknown process, they rely on a set of absolutely calibrated measurements. But many technologies (e.g., solid-state qubits) admit only a single native measurement basis, and other bases are measured using unitary control. So tomography becomes circular - tomographic protocols are using gates to calibrate themselves! Gate-set tomography confronts this problem head-on and resolves it by treating gates relationally. We abandon all assumptions about what a given gate operation does, and characterize entire universal gate sets from the ground up using only the observed statistics of an [unknown] 2-outcome measurement after various strings of [unknown] gate operations. The accuracy and reliability of the resulting estimate depends critically on which gate strings are used, and benefits greatly from adaptivity. Sandia National Labs is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Dept. of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000

  16. A quantum Fredkin gate (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Patel, Raj B.; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C.; Pryde, Geoff J.

    2016-10-01

    One of the greatest challenges in modern science is the realisation of quantum computers which, as their scale increases, will allow enhanced performance of tasks across many areas of quantum information processing. Quantum logic gates play a vital role in realising these applications by carrying out the elementary operations on the qubits; a key aim is minimising the resources needed to build these gates into useful circuits. While the salient features of a quantum computer have been shown in proof-of-principle experiments, e.g., single- and two-qubit gates, difficulties in scaling quantum systems to encode and manipulate multiple qubits has hindered demonstrations of more complex operations. This is exemplified by the classical Fredkin (or controlled-SWAP) gate [1] for which, despite many theoretical proposals [2,3] relying on concatenating multiple two-qubit gates, a quantum analogue has yet to be realised. Here, by directly adding control to a two-qubit SWAP unitary [4], we use photonic qubit logic to report the first experimental demonstration of a quantum Fredkin gate [5]. Our scheme uses linear optics and improves on the overall probability of success by an order of magnitude over previous proposals [2,3]. This optical approach allows us to add control an arbitrary black-box unitary which is otherwise forbidden in the standard circuit model [6]. Additionally, the action of our gate exhibits quantum coherence allowing the generation of the highest fidelity three-photon GHZ states to date. The quantum Fredkin gate has many applications in quantum computing, quantum measurements [7] and cryptography [8,9]. Using our scheme, we apply the Fredkin gate to the task of direct measurements of the purity and state overlap of a quantum system [7] without recourse to quantum state tomography.

  17. GADL: A gate array description language

    NASA Astrophysics Data System (ADS)

    Lippens, P. E. R.; Slenter, A. G. J.

    1987-01-01

    A way to map digital networks onto gate array images is described. A language to describe gate array images, design rules for the wiring, and arbitrary specified macros from image dependent libraries is defined. A data base is generated by compiling the description of a gate array family in terms of the above items. Place and route software is automatically conditioned to implement arbitrary specifications of a digital system in terms of a netlist. The performance of the system is demonstrated for various practical situations.

  18. Hybrid benchmarking of arbitrary quantum gates

    NASA Astrophysics Data System (ADS)

    Chasseur, Tobias; Reich, Daniel M.; Koch, Christiane P.; Wilhelm, Frank K.

    2017-06-01

    We present a protocol for interleaved randomized benchmarking of arbitrary quantum gates using Monte Carlo sampling of quantum states. It is generally applicable, including non-Clifford gates while preserving key advantages of randomized benchmarking such as error amplification as well as independence from state preparation and measurement errors. This property is crucial for implementations in many contemporary systems. Although the protocol scales exponentially in the number of qubits, it is superior to direct Monte Carlo sampling of the average gate fidelity in both the total number of experiments by orders of magnitude and savings in classical preprocessing, that are exponential.

  19. The gating of the CFTR channel.

    PubMed

    Moran, Oscar

    2017-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel expressed in the apical membrane of epithelia. Mutations in the CFTR gene are the cause of cystsic fibrosis. CFTR is the only ABC-protein that constitutes an ion channel pore forming subunit. CFTR gating is regulated in complex manner as phosphorylation is mandatory for channel activity and gating is directly regulated by binding of ATP to specific intracellular sites on the CFTR protein. This review covers our current understanding on the gating mechanism in CFTR and illustrates the relevance of alteration of these mechanisms in the onset of cystic fibrosis.

  20. Stay vane and wicket gate relationship study

    SciTech Connect

    None, None

    2005-01-19

    This report evaluates potential environmental and performance gains that can be achieved in a Kaplan turbine through non-structural modifications to stay vane and wicket gate assemblies. This summary is based primarily on data and conclusions drawn from models and studies of Lower Granite Dam. Based on this investigation, the study recommends (1) a proof of concept at Lower Granite Dam to establish predicted improvements for the existing turbine and to further refine the stay vane wicket gate designs for fish passage; and (2) consideration of the stay vane wicket gate systems in any future turbine rehabilitation studies.

  1. Diagonal gates in the Clifford hierarchy

    NASA Astrophysics Data System (ADS)

    Cui, Shawn X.; Gottesman, Daniel; Krishna, Anirudh

    2017-01-01

    The Clifford hierarchy is a set of gates that appears in the theory of fault-tolerant quantum computation, but its precise structure remains elusive. We give a complete characterization of the diagonal gates in the Clifford hierarchy for prime-dimensional qudits. They turn out to be pmth roots of unity raised to polynomial functions of the basis state to which they are applied, and we determine which level of the Clifford hierarchy a given gate sits in based on m and the degree of the polynomial.

  2. Gate-assisted turn-off thyristor

    NASA Technical Reports Server (NTRS)

    Lowry, L. R.; Page, D. J.; Schlegel, E. S.

    1978-01-01

    1,000-volt, 200-ampere gate-assisted turn-off thyristor has been developed for power circuits requiring high efficiency, small size, and low weight. Design features include shunted cathode for high dV/dt capability. Cathode in interdigitated with dynamic gate for fast, low-loss switching. Operating frequency exceeds 20 kHz with overall energy dissipation of less that 12 mJ per pulse for typical 20-microsecond half-sine waveform. Device has turn-on time of 2 microseconds and turn-off time as short as 3 microseconds with only 2 amperes of gate drive.

  3. Quantum gates and their coexisting geometric phases

    SciTech Connect

    Wu Lianao; Bishop, C. Allen; Byrd, Mark S.

    2011-08-15

    Geometric phases arise naturally in a variety of quantum systems with observable consequences. They also arise in quantum computations when dressed states are used in gating operations. Here we show how they arise in these gating operations and how one may take advantage of the dressed states producing them. Specifically, we show that for a given, but arbitrary Hamiltonian, and at an arbitrary time {tau}, there always exists a set of dressed states such that a given gate operation can be performed by the Hamiltonian up to a phase {phi}. The phase is a sum of a dynamical phase and a geometric phase. We illustrate the dressed phase for several systems.

  4. Efficient Design of Exclusive-Or Gate using 5-Input Majority Gate in QCA

    NASA Astrophysics Data System (ADS)

    Jaiswal, Ramanand; Nath Sasamal, Trailokya

    2017-08-01

    Quantum dot cellular automata (QCA) is one of the emerging technology that has the capability of replacing the CMOS based technology at nano scale level. Majority gates and inverter are the principle elements in QCA to design any circuit. In this work, we propose a new 5-input majority gate. The new proposed gate reduces number of required cell, area and power consumption. The study of power dissipation is also explained using power estimator tool QCAPro. QCA designer 2.0.3 is used to validate the majority gate layout and their functionality. Furthermore, an XOR gate based on QCA are designed using proposed majority gate. Layout and simulation results show the improvement of proposed circuit over previous designed circuits.

  5. Gate assisted turn-off thyristor with cathode shunts and dynamic gate

    NASA Technical Reports Server (NTRS)

    Schlegel, E. S.; Page, D. J.

    1976-01-01

    A 1,000-V, 200-A gate-assisted turn-off thyristor (GATT) is described, whose design features include an interdigitated shunted cathode, a dynamic gate, a means for optimizing the carrier lifetime level, and a bypass diode. The device physics of gate-assisted turn-off are reviewed. Based on this, improvements in the design are described. It is shown that a prime failure mode can be eliminated and that the gate-assist signal voltage can be substantially decreased by employing a shunted cathode emitter. The test data show excellent turn-on characteristics due to the dynamic gate and the long perimeter of the edge of the main cathode. Turn-off times as short as 3 microsec are obtained. The combination of controlling the carrier lifetime with a precisely controlled and easily variable irradiation dose of high energy electrons with gate assist current provides for simple, precision tailoring of the device characteristics to the intended application.

  6. Gate assisted turn-off thyristor with cathode shunts and dynamic gate

    NASA Technical Reports Server (NTRS)

    Schlegel, E. S.; Page, D. J.

    1976-01-01

    A 1,000-V, 200-A gate-assisted turn-off thyristor (GATT) is described, whose design features include an interdigitated shunted cathode, a dynamic gate, a means for optimizing the carrier lifetime level, and a bypass diode. The device physics of gate-assisted turn-off are reviewed. Based on this, improvements in the design are described. It is shown that a prime failure mode can be eliminated and that the gate-assist signal voltage can be substantially decreased by employing a shunted cathode emitter. The test data show excellent turn-on characteristics due to the dynamic gate and the long perimeter of the edge of the main cathode. Turn-off times as short as 3 microsec are obtained. The combination of controlling the carrier lifetime with a precisely controlled and easily variable irradiation dose of high energy electrons with gate assist current provides for simple, precision tailoring of the device characteristics to the intended application.

  7. Mechanosensitive Gating of Kv Channels

    PubMed Central

    Morris, Catherine E.; Prikryl, Emil A.; Joós, Béla

    2015-01-01

    K-selective voltage-gated channels (Kv) are multi-conformation bilayer-embedded proteins whose mechanosensitive (MS) Popen(V) implies that at least one conformational transition requires the restructuring of the channel-bilayer interface. Unlike Morris and colleagues, who attributed MS-Kv responses to a cooperative V-dependent closed-closed expansion↔compaction transition near the open state, Mackinnon and colleagues invoke expansion during a V-independent closed↔open transition. With increasing membrane tension, they suggest, the closed↔open equilibrium constant, L, can increase >100-fold, thereby taking steady-state Popen from 0→1; “exquisite sensitivity to small…mechanical perturbations”, they state, makes a Kv “as much a mechanosensitive…as…a voltage-dependent channel”. Devised to explain successive gK(V) curves in excised patches where tension spontaneously increased until lysis, their L-based model falters in part because of an overlooked IK feature; with recovery from slow inactivation factored in, their g(V) datasets are fully explained by the earlier model (a MS V-dependent closed-closed transition, invariant L≥4). An L-based MS-Kv predicts neither known Kv time courses nor the distinctive MS responses of Kv-ILT. It predicts Kv densities (hence gating charge per V-sensor) several-fold different from established values. If opening depended on elevated tension (L-based model), standard gK(V) operation would be compromised by animal cells’ membrane flaccidity. A MS V-dependent transition is, by contrast, unproblematic on all counts. Since these issues bear directly on recent findings that mechanically-modulated Kv channels subtly tune pain-related excitability in peripheral mechanoreceptor neurons we undertook excitability modeling (evoked action potentials). Kvs with MS V-dependent closed-closed transitions produce nuanced mechanically-modulated excitability whereas an L-based MS-Kv yields extreme, possibly excessive

  8. 7. DETAIL VIEW OF TAINTER GATE PIER AND NONSUBMERSIBLE TAINTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. DETAIL VIEW OF TAINTER GATE PIER AND NON-SUBMERSIBLE TAINTER GATES DURING ERECTION, SHOWING LEFT GATE IN OPEN POSITION AND RIGHT GATE IN CLOSED POSITION, LOOKING NORTH (UPSTREAM). NOTE TEMPORARY SERVICE BRIDGE. - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  9. 105. DAM TAINTER GATE SUBMERGIBLE SECTION & ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    105. DAM - TAINTER GATE - SUBMERGIBLE - SECTION & ELEVATION (ML-8-48/8-FS) June 1935 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  10. 103. DAM TAINTER GATE NONSUBMERGIBLE SECTION & ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    103. DAM - TAINTER GATE - NON-SUBMERGIBLE - SECTION & ELEVATION (ML-8-48/1-FS) June 1935 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  11. 102. DAM TAINTER GATE SUBMERGIBLE DESIGN DATA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    102. DAM - TAINTER GATE - SUBMERGIBLE - DESIGN DATA - CHANNEL RIBS (ML-8-48/C-FS) June 1935 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  12. Synthesizing Biomolecule-based Boolean Logic Gates

    PubMed Central

    Miyamoto, Takafumi; Razavi, Shiva; DeRose, Robert; Inoue, Takanari

    2012-01-01

    One fascinating recent avenue of study in the field of synthetic biology is the creation of biomolecule-based computers. The main components of a computing device consist of an arithmetic logic unit, the control unit, memory, and the input and output devices. Boolean logic gates are at the core of the operational machinery of these parts, hence to make biocomputers a reality, biomolecular logic gates become a necessity. Indeed, with the advent of more sophisticated biological tools, both nucleic acid- and protein-based logic systems have been generated. These devices function in the context of either test tubes or living cells and yield highly specific outputs given a set of inputs. In this review, we discuss various types of biomolecular logic gates that have been synthesized, with particular emphasis on recent developments that promise increased complexity of logic gate circuitry, improved computational speed, and potential clinical applications. PMID:23526588

  13. Mechanical gating of a mechanochemical reaction cascade

    PubMed Central

    Wang, Junpeng; Kouznetsova, Tatiana B.; Boulatov, Roman; Craig, Stephen L.

    2016-01-01

    Covalent polymer mechanochemistry offers promising opportunities for the control and engineering of reactivity. To date, covalent mechanochemistry has largely been limited to individual reactions, but it also presents potential for intricate reaction systems and feedback loops. Here we report a molecular architecture, in which a cyclobutane mechanophore functions as a gate to regulate the activation of a second mechanophore, dichlorocyclopropane, resulting in a mechanochemical cascade reaction. Single-molecule force spectroscopy, pulsed ultrasonication experiments and DFT-level calculations support gating and indicate that extra force of >0.5 nN needs to be applied to a polymer of gated gDCC than of free gDCC for the mechanochemical isomerization gDCC to proceed at equal rate. The gating concept provides a mechanism by which to regulate stress-responsive behaviours, such as load-strengthening and mechanochromism, in future materials designs. PMID:27848956

  14. Time-gated optical projection tomography.

    PubMed

    Bassi, Andrea; Brida, Daniele; D'Andrea, Cosimo; Valentini, Gianluca; Cubeddu, Rinaldo; De Silvestri, Sandro; Cerullo, Giulio

    2010-08-15

    We present an imaging technique that combines optical projection tomography with ballistic imaging using ultrafast time gating. The method provides high-resolution reconstruction of scattering samples and is suitable for three-dimensional (3D) imaging of biological models.

  15. Silicon-gate CMOS/SOS processing

    NASA Technical Reports Server (NTRS)

    Ramondetta, P.

    1979-01-01

    Major silicon-gate CMOS/SOS processes are described. Sapphire substrate preparation is also discussed, as well as the following process variations: (1) the double epi process; and (2) ion implantation.

  16. Active gated imaging in driver assistance system

    NASA Astrophysics Data System (ADS)

    Grauer, Yoav

    2014-04-01

    In this paper, we shall present the active gated imaging system (AGIS) in relation to the automotive field. AGIS is based on a fast-gated camera and pulsed illuminator, synchronized in the time domain to record images of a certain range of interest. A dedicated gated CMOS imager sensor and near infra-red (NIR) pulsed laser illuminator, is presented in this paper to provide active gated technology. In recent years, we have developed these key components and learned the system parameters, which are most beneficial to nighttime (in all weather conditions) driving in terms of field of view, illumination profile, resolution, and processing power. We shall present our approach of a camera-based advanced driver assistance systems (ADAS) named BrightEye™, which makes use of the AGIS technology in the automotive field.

  17. Current profiles in gated graphene ribbons

    NASA Astrophysics Data System (ADS)

    Cresti, Alessandro; Grosso, Giuseppe; Pastori Parravicini, Giuseppe

    2008-03-01

    We simulate stationary current distribution in graphene ribbons in the presence of top gate potentials, by means of the nonequilibrium Keldysh-Green's function formalism within a tight-binding model. In the absence of magnetic fields and in the presence of a model potential barrier, we observe the Klein paradox, where electrons turn into holes in the gated region and again into electrons beyond it. We establish a connection between the band structure at the corner points of the Brillouin zone and Klein paradox, and give a pictorial description of conductive channels. In the presence of high magnetic fields, transport currents are chiral and flow along the edges of the ribbon. The intensity and sign of the potential barrier with respect to the Fermi energy influence the nature (electron/hole) of the carriers inside the gated region and determine the edge involved in the transport process. We demonstrate that manipulation of currents in the ribbon can be obtained by external gates.

  18. Digital gate pulse generator for cycloconverter control

    DOEpatents

    Klein, Frederick F.; Mutone, Gioacchino A.

    1989-01-01

    The present invention provides a digital gate pulse generator which controls the output of a cycloconverter used for electrical power conversion applications by determining the timing and delivery of the firing pulses to the switching devices in the cycloconverter. Previous gate pulse generators have been built with largely analog or discrete digital circuitry which require many precision components and periodic adjustment. The gate pulse generator of the present invention utilizes digital techniques and a predetermined series of values to develop the necessary timing signals for firing the switching device. Each timing signal is compared with a reference signal to determine the exact firing time. The present invention is significantly more compact than previous gate pulse generators, responds quickly to changes in the output demand and requires only one precision component and no adjustments.

  19. Greening the Golden Gate National Recreation Area

    EPA Pesticide Factsheets

    The Golden Gate National Recreation Area was recognized a 2016 Federal Green Challenge Award for making significant strides to reduce its carbon footprint with the goal of becoming a carbon neutral park.

  20. Optically gated beating-heart imaging

    PubMed Central

    Taylor, Jonathan M.

    2014-01-01

    The constant motion of the beating heart presents an obstacle to clear optical imaging, especially 3D imaging, in small animals where direct optical imaging would otherwise be possible. Gating techniques exploit the periodic motion of the heart to computationally “freeze” this movement and overcome motion artifacts. Optically gated imaging represents a recent development of this, where image analysis is used to synchronize acquisition with the heartbeat in a completely non-invasive manner. This article will explain the concept of optical gating, discuss a range of different implementation strategies and their strengths and weaknesses. Finally we will illustrate the usefulness of the technique by discussing applications where optical gating has facilitated novel biological findings by allowing 3D in vivo imaging of cardiac myocytes in their natural environment of the beating heart. PMID:25566083

  1. Synthesizing biomolecule-based Boolean logic gates.

    PubMed

    Miyamoto, Takafumi; Razavi, Shiva; DeRose, Robert; Inoue, Takanari

    2013-02-15

    One fascinating recent avenue of study in the field of synthetic biology is the creation of biomolecule-based computers. The main components of a computing device consist of an arithmetic logic unit, the control unit, memory, and the input and output devices. Boolean logic gates are at the core of the operational machinery of these parts, and hence to make biocomputers a reality, biomolecular logic gates become a necessity. Indeed, with the advent of more sophisticated biological tools, both nucleic acid- and protein-based logic systems have been generated. These devices function in the context of either test tubes or living cells and yield highly specific outputs given a set of inputs. In this review, we discuss various types of biomolecular logic gates that have been synthesized, with particular emphasis on recent developments that promise increased complexity of logic gate circuitry, improved computational speed, and potential clinical applications.

  2. Extending Double Optical Gating to the Midinfrared

    NASA Astrophysics Data System (ADS)

    Gorman, Timothy; Camper, Antoine; Agostini, Pierre; Dimauro, Louis

    2015-05-01

    In the past decade there has been great interest in creating broadband isolated attosecond pulses (IAPs). Primarily these IAPs have been generated using Ti:Sapphire 800nm short pulses, namely through spatiotemporal gating with the attosecond lighthouse technique, amplitude gating, polarization gating, and double optical gating (DOG). Here we present theoretical calculations and experimental investigations into extending DOG to using a 2 μm driving wavelength, the benefits of which include extended harmonic cutoff and longer input driving pulse durations. It is proposed that broadband IAPs with cutoffs extending up to 250 eV can be generated in Argon by using >30 fs pulses from the passively-CEP stabilized 2 μm idler out of an optical parametric amplifier combined with a collinear DOG experimental setup.

  3. Mechanical gating of a mechanochemical reaction cascade

    NASA Astrophysics Data System (ADS)

    Wang, Junpeng; Kouznetsova, Tatiana B.; Boulatov, Roman; Craig, Stephen L.

    2016-11-01

    Covalent polymer mechanochemistry offers promising opportunities for the control and engineering of reactivity. To date, covalent mechanochemistry has largely been limited to individual reactions, but it also presents potential for intricate reaction systems and feedback loops. Here we report a molecular architecture, in which a cyclobutane mechanophore functions as a gate to regulate the activation of a second mechanophore, dichlorocyclopropane, resulting in a mechanochemical cascade reaction. Single-molecule force spectroscopy, pulsed ultrasonication experiments and DFT-level calculations support gating and indicate that extra force of >0.5 nN needs to be applied to a polymer of gated gDCC than of free gDCC for the mechanochemical isomerization gDCC to proceed at equal rate. The gating concept provides a mechanism by which to regulate stress-responsive behaviours, such as load-strengthening and mechanochromism, in future materials designs.

  4. Funding announcements from federal government, Gates Foundation.

    PubMed

    Garmaise, David

    2007-05-01

    In two separate announcements, in December 2006 and February 2007, the federal government allocated new funding for HIV/AIDS. The latter announcement was accompanied by a pledge from the Gates Foundation.

  5. Integrated photonic quantum gates for polarization qubits

    PubMed Central

    Crespi, Andrea; Ramponi, Roberta; Osellame, Roberto; Sansoni, Linda; Bongioanni, Irene; Sciarrino, Fabio; Vallone, Giuseppe; Mataloni, Paolo

    2011-01-01

    The ability to manipulate quantum states of light by integrated devices may open new perspectives both for fundamental tests of quantum mechanics and for novel technological applications. However, the technology for handling polarization-encoded qubits, the most commonly adopted approach, is still missing in quantum optical circuits. Here we demonstrate the first integrated photonic controlled-NOT (CNOT) gate for polarization-encoded qubits. This result has been enabled by the integration, based on femtosecond laser waveguide writing, of partially polarizing beam splitters on a glass chip. We characterize the logical truth table of the quantum gate demonstrating its high fidelity to the expected one. In addition, we show the ability of this gate to transform separable states into entangled ones and vice versa. Finally, the full accessibility of our device is exploited to carry out a complete characterization of the CNOT gate through a quantum process tomography. PMID:22127062

  6. Smart gating membranes with in situ self-assembled responsive nanogels as functional gates

    PubMed Central

    Luo, Feng; Xie, Rui; Liu, Zhuang; Ju, Xiao-Jie; Wang, Wei; Lin, Shuo; Chu, Liang-Yin

    2015-01-01

    Smart gating membranes, inspired by the gating function of ion channels across cell membranes, are artificial membranes composed of non-responsive porous membrane substrates and responsive gates in the membrane pores that are able to dramatically regulate the trans-membrane transport of substances in response to environmental stimuli. Easy fabrication, high flux, significant response and strong mechanical strength are critical for the versatility of such smart gating membranes. Here we show a novel and simple strategy for one-step fabrication of smart gating membranes with three-dimensionally interconnected networks of functional gates, by self-assembling responsive nanogels on membrane pore surfaces in situ during a vapor-induced phase separation process for membrane formation. The smart gating membranes with in situ self-assembled responsive nanogels as functional gates show large flux, significant response and excellent mechanical property simultaneously. Because of the easy fabrication method as well as the concurrent enhancement of flux, response and mechanical property, the proposed smart gating membranes will expand the scope of membrane applications, and provide ever better performances in their applications. PMID:26434387

  7. Gate Rupture in Ultra-Thin Gate Oxides Irradiated With Heavy Ions

    NASA Astrophysics Data System (ADS)

    Silvestri, Marco; Gerardin, Simone; Paccagnella, Alessandro; Ghidini, Gabriella

    2009-08-01

    We investigated the combined effect of heavy-ion irradiation and large applied bias on the dielectric breakdown of ultra-thin gate oxides, analyzing the impact of border regions through dedicated test structures. We found that the irradiation bias polarity plays a fundamental role, with inversion being more detrimental than accumulation for the onset of gate rupture. Moreover, the average voltage to breakdown was, under certain conditions, lower in structures more closely resembling real MOSFETs, as compared to those commonly used for the evaluation of Single Event Gate Rupture. These findings raise some important hardness assurance issues concerning the integrity of gate oxides in radiation environments.

  8. The effect of pregabalin on sensorimotor gating in 'low' gating humans and mice.

    PubMed

    Acheson, Dean T; Stein, Murray B; Paulus, Martin P; Geyer, Mark A; Risbrough, Victoria B

    2012-09-01

    Pregabalin, an anticonvulsant and anxiolytic compound that binds to α2-δ auxiliary subunit Types 1 and 2 of voltage-gated calcium channels, has been shown to reduce excitatory neurotransmission partially through modulation of glutamatergic signaling. Prepulse inhibition (PPI) of startle is an operational measure of sensorimotor gating impacted by disruption of the glutamatergic system and is reduced in schizophrenia patients. Dysregulation of the glutamatergic system has also been implicated in the pathophysiology of schizophrenia. Here we tested the hypothesis that pregabalin may ameliorate PPI in a model of deficient gating in humans and mice. In study 1, 14 healthy human subjects participated in a within subjects, cross-over study with placebo, 50 mg or 200 mg pregabalin treatment prior to undergoing a PPI task. In study 2, 24 C57BL/6 mice underwent a similar procedure with vehicle, 30 and 100 mg/kg dose treatments. In both studies, subjects were assigned to a "Low" or "High" gating group using a median split procedure based on their PPI performance during placebo/vehicle. Drug effects were then examined across these groups. In humans, pregabalin treatment significantly increased PPI performance in the "low gating" group. In mice, pregabalin treatment significantly increased PPI in the low gating group but reduced PPI in the high gating group. Across species, pregabalin treatment improves PPI in subjects with low gating. These data support further exploration of pregabalin as a potential treatment for disorders characterized by sensorimotor gating deficits and glutamatergic hypersignaling, such as schizophrenia.

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

    PubMed

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

    2017-03-06

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

  10. GaTe semiconductor for radiation detection

    DOEpatents

    Payne, Stephen A [Castro Valley, CA; Burger, Arnold [Nashville, TN; Mandal, Krishna C [Ashland, MA

    2009-06-23

    GaTe semiconductor is used as a room-temperature radiation detector. GaTe has useful properties for radiation detectors: ideal bandgap, favorable mobilities, low melting point (no evaporation), non-hygroscopic nature, and availability of high-purity starting materials. The detector can be used, e.g., for detection of illicit nuclear weapons and radiological dispersed devices at ports of entry, in cities, and off shore and for determination of medical isotopes present in a patient.

  11. Dual-Gated Volumetric Modulated Arc Therapy.

    PubMed

    Fahimian, Benjamin; Wu, Junqing; Wu, Huanmei; Geneser, Sarah; Xing, Lei

    2014-09-25

    Gated Volumetric Modulated Arc Therapy (VMAT) is an emerging radiation therapy modality for treatment of tumors affected by respiratory motion. However, gating significantly prolongs the treatment time, as delivery is only activated during a single respiratory phase. To enhance the efficiency of gated VMAT delivery, a novel dual-gated VMAT (DG-VMAT) technique, in which delivery is executed at both exhale and inhale phases in a given arc rotation, is developed and experimentally evaluated. Arc delivery at two phases is realized by sequentially interleaving control points consisting of MUs, MLC sequences, and angles of VMAT plans generated at the exhale and inhale phases. Dual-gated delivery is initiated when a respiration gating signal enters the exhale window; when the exhale delivery concludes, the beam turns off and the gantry rolls back to the starting position for the inhale window. The process is then repeated until both inhale and exhale arcs are fully delivered. DG-VMAT plan delivery accuracy was assessed using a pinpoint chamber and diode array phantom undergoing programmed motion. DG-VMAT delivery was experimentally implemented through custom XML scripting in Varian's TrueBeam™ STx Developer Mode. Relative to single gated delivery at exhale, the treatment time was improved by 95.5% for a sinusoidal breathing pattern. The pinpoint chamber dose measurement agreed with the calculated dose within 0.7%. For the DG-VMAT delivery, 97.5% of the diode array measurements passed the 3%/3 mm gamma criterion. The feasibility of DG-VMAT delivery scheme has been experimentally demonstrated for the first time. By leveraging the stability and natural pauses that occur at end-inspiration and end-exhalation, DG-VMAT provides a practical method for enhancing gated delivery efficiency by up to a factor of two.

  12. Multipulse interferometric frequency-resolved optical gating

    SciTech Connect

    Siders, C.W.; Siders, J.L.W.; Omenetto, F.G.; Taylor, A.J.

    1999-04-01

    The authors review multipulse interferometric frequency-resolved optical gating (MI-FROG) as a technique, uniquely suited for pump-probe coherent spectroscopy using amplified visible and near-infrared short-pulse systems and/or emissive targets, for time-resolving ultrafast phase shifts and intensity changes. Application of polarization-gate MI-FROG to the study of ultrafast ionization in gases is presented.

  13. Fast phase gates with trapped ions

    NASA Astrophysics Data System (ADS)

    Palmero, M.; Martínez-Garaot, S.; Leibfried, D.; Wineland, D. J.; Muga, J. G.

    2017-02-01

    We implement faster-than-adiabatic two-qubit phase gates using smooth state-dependent forces. The forces are designed to leave no final motional excitation, independently of the initial motional state in the harmonic small-oscillations limit. They are simple, explicit functions of time and the desired logical phase of the gate, and are based on quadratic invariants of motion and Lewis-Riesenfeld phases of the normal modes.

  14. Hysteresis in voltage-gated channels.

    PubMed

    Villalba-Galea, Carlos A

    2016-09-30

    Ion channels constitute a superfamily of membrane proteins found in all living creatures. Their activity allows fast translocation of ions across the plasma membrane down the ion's transmembrane electrochemical gradient, resulting in a difference in electrical potential across the plasma membrane, known as the membrane potential. A group within this superfamily, namely voltage-gated channels, displays activity that is sensitive to the membrane potential. The activity of voltage-gated channels is controlled by the membrane potential, while the membrane potential is changed by these channels' activity. This interplay produces variations in the membrane potential that have evolved into electrical signals in many organisms. These signals are essential for numerous biological processes, including neuronal activity, insulin release, muscle contraction, fertilization and many others. In recent years, the activity of the voltage-gated channels has been observed not to follow a simple relationship with the membrane potential. Instead, it has been shown that the activity of voltage-gated channel displays hysteresis. In fact, a growing number of evidence have demonstrated that the voltage dependence of channel activity is dynamically modulated by activity itself. In spite of the great impact that this property can have on electrical signaling, hysteresis in voltage-gated channels is often overlooked. Addressing this issue, this review provides examples of voltage-gated ion channels displaying hysteretic behavior. Further, this review will discuss how Dynamic Voltage Dependence in voltage-gated channels can have a physiological role in electrical signaling. Furthermore, this review will elaborate on the current thoughts on the mechanism underlying hysteresis in voltage-gated channels.

  15. Quantum teleportation of optical quantum gates.

    PubMed

    Bartlett, Stephen D; Munro, William J

    2003-03-21

    We show that a universal set of gates for quantum computation with optics can be quantum teleported through the use of EPR entangled states, homodyne detection, and linear optics and squeezing operations conditioned on measurement outcomes. This scheme may be used for fault-tolerant quantum computation in any optical scheme (qubit or continuous-variable). The teleportation of nondeterministic nonlinear gates employed in linear optics quantum computation is discussed.

  16. Advanced logic gates for ultrafast network interchanges

    NASA Astrophysics Data System (ADS)

    Islam, Mohammed N.

    1995-08-01

    By overcoming speed bottlenecks from electronic switching as well as optical/electronic conversions, all-optical logic gates can permit further exploitation of the nearly 40 THz of bandwidth available from optical fibers. We focus on the use of optical solitons and all-optical logic gates to implement ultrafast ``interchanges'' or switching nodes on packet networks with speeds of 100 Gbit/s or greater. For example, all-optical logic gates have been demonstrated with speeds up to 200 Gbit/s, and they may be used to decide whether to add or drop a data packet. The overall goal of our effort is to demonstrate the key enabling technologies and their combination for header processing in 100 Gbit/s, time-division-multiplexed, packed switched networks. Soliton-based fiber logic gates are studied with the goal of combining attractive features of soliton-dragging logic gates, nonlinear loop mirrors, and erbium-doped fiber amplifiers to design logic gates with optimum switching energy, contrast ratio, and timing sensitivity. First, the experimental and numerical work studies low-latency soliton logic gates based on frequency shifts associated with cross-phase modulation. In preliminary experiments, switching in 15 m long low-birefringent fibers has been demonstrated with a contrast ratio of 2.73:1. Using dispersion-shifted fiber in the gate should lower the switching energy and improve the contrast ratio. Next, the low-birefringent fiber can be cross-spliced and wrapped into a nonlinear optical loop mirror to take advantage of mechanisms from both soliton dragging and loop mirrors. The resulting device can have low switching energy and a timing window that results from a combination of soliton dragging and the loop mirror mechanisms.

  17. Modulation of CFTR gating by permeant ions

    PubMed Central

    Yeh, Han-I; Yeh, Jiunn-Tyng

    2015-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is unique among ion channels in that after its phosphorylation by protein kinase A (PKA), its ATP-dependent gating violates microscopic reversibility caused by the intimate involvement of ATP hydrolysis in controlling channel closure. Recent studies suggest a gating model featuring an energetic coupling between opening and closing of the gate in CFTR’s transmembrane domains and association and dissociation of its two nucleotide-binding domains (NBDs). We found that permeant ions such as nitrate can increase the open probability (Po) of wild-type (WT) CFTR by increasing the opening rate and decreasing the closing rate. Nearly identical effects were seen with a construct in which activity does not require phosphorylation of the regulatory domain, indicating that nitrate primarily affects ATP-dependent gating steps rather than PKA-dependent phosphorylation. Surprisingly, the effects of nitrate on CFTR gating are remarkably similar to those of VX-770 (N-(2,4-Di-tert-butyl-5-hydroxyphenyl)-4-oxo-1,4-dihydroquinoline-3-carboxamide), a potent CFTR potentiator used in clinics. These include effects on single-channel kinetics of WT CFTR, deceleration of the nonhydrolytic closing rate, and potentiation of the Po of the disease-associated mutant G551D. In addition, both VX-770 and nitrate increased the activity of a CFTR construct lacking NBD2 (ΔNBD2), indicating that these gating effects are independent of NBD dimerization. Nonetheless, whereas VX-770 is equally effective when applied from either side of the membrane, nitrate potentiates gating mainly from the cytoplasmic side, implicating a common mechanism for gating modulation mediated through two separate sites of action. PMID:25512598

  18. Boolean gates on actin filaments

    NASA Astrophysics Data System (ADS)

    Siccardi, Stefano; Tuszynski, Jack A.; Adamatzky, Andrew

    2016-01-01

    Actin is a globular protein which forms long polar filaments in the eukaryotic cytoskeleton. Actin networks play a key role in cell mechanics and cell motility. They have also been implicated in information transmission and processing, memory and learning in neuronal cells. The actin filaments have been shown to support propagation of voltage pulses. Here we apply a coupled nonlinear transmission line model of actin filaments to study interactions between voltage pulses. To represent digital information we assign a logical TRUTH value to the presence of a voltage pulse in a given location of the actin filament, and FALSE to the pulse's absence, so that information flows along the filament with pulse transmission. When two pulses, representing Boolean values of input variables, interact, then they can facilitate or inhibit further propagation of each other. We explore this phenomenon to construct Boolean logical gates and a one-bit half-adder with interacting voltage pulses. We discuss implications of these findings on cellular process and technological applications.

  19. Range gated strip proximity sensor

    DOEpatents

    McEwan, T.E.

    1996-12-03

    A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance. 6 figs.

  20. Range gated strip proximity sensor

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance.

  1. Gate-set tomography and beyond

    NASA Astrophysics Data System (ADS)

    Blume-Kohout, Robin

    Four years ago, there was no reliable way to characterize and debug quantum gates. Process tomography required perfectly pre-calibrated gates, while randomized benchmarking only yielded an overall error rate. Gate-set tomography (GST) emerged around 2012-13 in several variants (most notably at IBM; see PRA 87, 062119) to address this need, providing complete and calibration-free characterization of gates. At Sandia, we have pushed the capabilities of GST well beyond these initial goals. In this talk, I'll demonstrate our open web interface, show how we characterize gates with accuracy at the Heisenberg limit, discuss how we put error bars on the results, and present experimental GST estimates with 1e-5 error bars. I'll also present preliminary results of GST on 2-qubit gates, including a brief survey of the tricks we use to make it possible. I'll conclude with an analysis of GST's limitations (e.g., it scales poorly), and the techniques under development for characterizing and debugging larger (3+ qubit) systems.

  2. Shielded silicon gate complementary MOS integrated circuit.

    NASA Technical Reports Server (NTRS)

    Lin, H. C.; Halsor, J. L.; Hayes, P. J.

    1972-01-01

    An electrostatic shield for complementary MOS integrated circuits was developed to minimize the adverse effects of stray electric fields created by the potentials in the metal interconnections. The process is compatible with silicon gate technology. N-doped polycrystalline silicon was used for all the gates and the shield. The effectiveness of the shield was demonstrated by constructing a special field plate over certain transistors. The threshold voltages obtained on an oriented silicon substrate ranged from 1.5 to 3 V for either channel. Integrated inverters performed satisfactorily from 3 to 15 V, limited at the low end by the threshold voltages and at the high end by the drain breakdown voltage of the n-channel transistors. The stability of the new structure with an n-doped silicon gate as measured by the shift in C-V curve under 200 C plus or minus 20 V temperature-bias conditions was better than conventional aluminum gate or p-doped silicon gate devices, presumably due to the doping of gate oxide with phosphorous.

  3. Radiation-Insensitive Inverse Majority Gates

    NASA Technical Reports Server (NTRS)

    Manohara, Harish; Mojarradi, Mohammad

    2008-01-01

    To help satisfy a need for high-density logic circuits insensitive to radiation, it has been proposed to realize inverse majority gates as microscopic vacuum electronic devices. In comparison with solid-state electronic devices ordinarily used in logic circuits, vacuum electronic devices are inherently much less adversely affected by radiation and extreme temperatures. The proposed development would involve state-of-the-art micromachining and recent advances in the fabrication of carbon-nanotube-based field emitters. A representative three-input inverse majority gate would be a monolithic, integrated structure that would include three gate electrodes, six bundles of carbon nanotubes (serving as electron emitters) at suitable positions between the gate electrodes, and an overhanging anode. The bundles of carbon nanotubes would be grown on degenerately doped silicon substrates that would be parts of the monolithic structure. The gate electrodes would be fabricated as parts of the monolithic structure by means of a double-silicon-on-insulator process developed at NASA's Jet Propulsion Laboratory. The tops of the bundles of carbon nanotubes would lie below the plane of the tops of the gate electrodes. The particular choice of shapes, dimensions, and relative positions of the electrodes and bundles of carbon nanotubes would provide for both field emission of electrons from the bundles of carbon nanotubes and control of the electron current to obtain the inverse majority function, which is described in the paper.

  4. Sensory gating deficits in parents of schizophrenics

    SciTech Connect

    Waldo, M.; Madison, A.; Freedman, R.

    1995-12-18

    Although schizophrenia clusters in families, it is not inherited in Mendelian fashion. This suggests that there may be alternative phenotypic expressions of genes that convey risk for schizophrenia, such as more elementary physiological or biochemical defects. One proposed phenotype is impaired inhibitory gating of the auditory evoked potential to repeated stimuli. Normally, the amplitude of the P50 response to the second stimulus is significantly less than the response to the first, but this gating of response is generally impaired in schizophrenia. Clinically unaffected individuals within a pedigree who have both an ancestral and descendant history of schizophrenia may be useful for studying whether this physiological defect is a possible alternative phenotype. We have studied inhibitory gating of the auditory P50 response to pairs of auditory stimuli in 17 nuclear families. In 11, there was one parent who had another relative with a chronic psychotic illness, in addition to the schizophrenic proband. AR of the parents with family histories of schizophrenia had gating of the P50 response similar to their schizophrenia offspring, whereas only 7% of the parents without family history had gating of the P50 response in the abnormal range. These results support loss of gating of the auditory P50 wave as an inherited deficit related to schizophrenia and suggest that studies of parents may help elucidate the neurobiological expression of genes that convey risk for schizophrenia. 36 refs., 2 figs., 2 tabs.

  5. The evaluation of the flash gate board

    SciTech Connect

    Malyevac, D.S.; Leonard, R.G.

    1988-05-01

    The height of an overflow dam must be designed low enough to prevent the reservoir water level from exceeding a flood plain during flooding conditions. Because of this constraint, much of the available water storage area is wasted and the available pressure head for power generation will be less than maximum during normal conditions. Crest control gates alleviate this problem by providing a variable spillway height. The Flash Gate Board is a passive automatic crest control gate. Its purpose is to regulate flood water while providing increased water pressure for power generation or for additional water storage municipality. The governing equations for the Flash Gate Board system are derived and used to formulate models of system. Computer simulations are used to examine the system response in a variety of operating conditions. The results of these simulations are presented and discussed. The results include an investigation which developed an optimum gate height to maximize the potential of the Flash Gate Board. An experimental model was developed to verify analytical results and to provide additional insight. Conclusions from the study, recommendations for future work, and modifications for a trouble-free design are discussed. 26 refs., 30 figs., 3 tabs.

  6. Gated entry into the ciliary compartment

    PubMed Central

    Takao, Daisuke; Verhey, Kristen J

    2016-01-01

    Cilia and flagella play important roles in cell motility and cell signaling. These functions require that the cilium establishes and maintains a unique lipid and protein composition. Recent work indicates that a specialized region at the base of the cilium, the transition zone, serves as both a barrier to entry and a gate for passage of select components. For at least some cytosolic proteins, the barrier and gate functions are provided by a ciliary pore complex (CPC) that shares molecular and mechanistic properties with nuclear gating. Specifically, nucleoporins of the CPC limit the diffusional entry of cytosolic proteins in a size-dependent manner and enable the active transport of large molecules and complexes via targeting signals, importins, and the small G protein Ran. For membrane proteins, the septin protein SEPT2 is part of the barrier to entry whereas the gating function is carried out and/or regulated by proteins associated with ciliary diseases (ciliopathies) such as nephronophthisis (NPHP), Meckel-Gruber Syndrome (MKS) and Joubert Syndrome (JBTS). Here, we discuss the evidence behind these models of ciliary gating as well as the similarities to and differences from nuclear gating. PMID:26472341

  7. Gated SIT Vidicon Streak Tube

    NASA Astrophysics Data System (ADS)

    Dunbar, D. L.; Yates, G. J.; Black, J. P.

    1986-01-01

    A recently developed prototype streak tube designed to produce high gain and resolution by incorporating the streak and readout functions in one envelope thereby minimizing photon-to-charge transformations and eliminating external coupling losses is presented. The tube is based upon a grid-gated Silicon-Intensified-Target Vidicon (SITV) with integral Focus Projection Scan (FPS) TV readout. Demagnifying electron optics (m=0.63) in the image section map the 40-mm-diameter photocathode image unto a 25-mm-diameter silicon target where gains >= 103 are achieved with only 10 KV accelerating voltage. This is compared with much lower gains (~ 50) at much higher voltages (~ 30 KV) reported for streak tubes using phosphor screens. Because SIT technology is well established means for electron imaging in vacuum, such fundamental problems as "backside thinning" required for electron imaging unto CCDs do not exist. The high spatial resolution (~ 30 1p/mm), variable scan formats, and high speed electrostatic deflection (250 mm2 areas are routinely rastered with 256 scan lines in 1.6 ms) available from FPS readout add versatility not available in CCD devices. Theoretical gain and spatial resolution for this design (developed jointly by Los Alamos National Laboratory and General Electric Co.) are compared with similar calculations and measured data obtained for RCA 73435 streaks fiber optically coupled to (1) 25-mm-diameter SIT FPS vidicons and (2) 40-mm-diameter MCPTs (proximity-focused microchannel plate image intensifier tubes) fiber optically coupled to 18-mm-diameter Sb2S3 FPS vidicons. Sweep sensitivity, shutter ratio, and record lengths for nanosecond duration (20 to 200 ns) streak applications are discussed.

  8. Controlled Logic Gates-Switch Gate and Fredkin Gate Based on Enzyme-Biocatalyzed Reactions Realized in Flow Cells.

    PubMed

    Fratto, Brian E; Katz, Evgeny

    2016-04-04

    Controlled logic gates, where the logic operations on the Data inputs are performed in the way determined by the Control signal, were designed in a chemical fashion. Specifically, the systems where the Data output signals directed to various output channels depending on the logic value of the Control input signal have been designed based on enzyme biocatalyzed reactions performed in a multi-cell flow system. In the Switch gate one Data signal was directed to one of two possible output channels depending on the logic value of the Control input signal. In the reversible Fredkin gate the routing of two Data signals between two output channels is controlled by the third Control signal. The flow devices were created using a network of flow cells, each modified with one enzyme that biocatalyzed one chemical reaction. The enzymatic cascade was realized by moving the solution from one reacting cell to another which were organized in a specific network. The modular design of the enzyme-based systems realized in the flow device allowed easy reconfiguration of the logic system, thus allowing simple extension of the logic operation from the 2-input/3-output channels in the Switch gate to the 3-input/3-output channels in the Fredkin gate. Further increase of the system complexity for realization of various logic processes is feasible with the use of the flow cell modular design.

  9. Analytical drain current formulation for gate dielectric engineered dual material gate-gate all around-tunneling field effect transistor

    NASA Astrophysics Data System (ADS)

    Madan, Jaya; Gupta, R. S.; Chaujar, Rishu

    2015-09-01

    In this work, an analytical drain current model for gate dielectric engineered (hetero dielectric)-dual material gate-gate all around tunnel field effect transistor (HD-DMG-GAA-TFET) has been developed. Parabolic approximation has been used to solve the two-dimensional (2D) Poisson equation with appropriate boundary conditions and continuity equations to evaluate analytical expressions for surface potential, electric field, tunneling barrier width and drain current. Further, the analog performance of the device is studied for three high-k dielectrics (Si3N4, HfO2, and ZrO2), and it has been investigated that the problem of lower ION, can be overcome by using the hetero-gate architecture. Moreover, the impact of scaling the gate oxide thickness and bias variations has also been studied. The HD-DMG-GAA-TFET shows an enhanced ION of the order of 10-4 A. The effectiveness of the proposed model is validated by comparing it with ATLAS device simulations.

  10. Gallium arsenide processing for gate array logic

    NASA Astrophysics Data System (ADS)

    Cole, Eric D.

    1989-09-01

    The development of a reliable and reproducible GaAs process was initiated for applications in gate array logic. Gallium Arsenide is an extremely important material for high speed electronic applications in both digital and analog circuits since its electron mobility is 3 to 5 times that of silicon, this allows for faster switching times for devices fabricated with it. Unfortunately GaAs is an extremely difficult material to process with respect to silicon and since it includes the arsenic component GaAs can be quite dangerous (toxic) especially during some heating steps. The first stage of the research was directed at developing a simple process to produce GaAs MESFETs. The MESFET (MEtal Semiconductor Field Effect Transistor) is the most useful, practical and simple active device which can be fabricated in GaAs. It utilizes an ohmic source and drain contact separated by a Schottky gate. The gate width is typically a few microns. Several process steps were required to produce a good working device including ion implantation, photolithography, thermal annealing, and metal deposition. A process was designed to reduce the total number of steps to a minimum so as to reduce possible errors. The first run produced no good devices. The problem occurred during an aluminum etch step while defining the gate contacts. It was found that the chemical etchant attacked the GaAs causing trenching and subsequent severing of the active gate region from the rest of the device. Thus all devices appeared as open circuits. This problem is being corrected and since it was the last step in the process correction should be successful. The second planned stage involves the circuit assembly of the discrete MESFETs into logic gates for test and analysis. Finally the third stage is to incorporate the designed process with the tested circuit in a layout that would produce the gate array as a GaAs integrated circuit.

  11. Gallium arsenide processing for gate array logic

    NASA Technical Reports Server (NTRS)

    Cole, Eric D.

    1989-01-01

    The development of a reliable and reproducible GaAs process was initiated for applications in gate array logic. Gallium Arsenide is an extremely important material for high speed electronic applications in both digital and analog circuits since its electron mobility is 3 to 5 times that of silicon, this allows for faster switching times for devices fabricated with it. Unfortunately GaAs is an extremely difficult material to process with respect to silicon and since it includes the arsenic component GaAs can be quite dangerous (toxic) especially during some heating steps. The first stage of the research was directed at developing a simple process to produce GaAs MESFETs. The MESFET (MEtal Semiconductor Field Effect Transistor) is the most useful, practical and simple active device which can be fabricated in GaAs. It utilizes an ohmic source and drain contact separated by a Schottky gate. The gate width is typically a few microns. Several process steps were required to produce a good working device including ion implantation, photolithography, thermal annealing, and metal deposition. A process was designed to reduce the total number of steps to a minimum so as to reduce possible errors. The first run produced no good devices. The problem occurred during an aluminum etch step while defining the gate contacts. It was found that the chemical etchant attacked the GaAs causing trenching and subsequent severing of the active gate region from the rest of the device. Thus all devices appeared as open circuits. This problem is being corrected and since it was the last step in the process correction should be successful. The second planned stage involves the circuit assembly of the discrete MESFETs into logic gates for test and analysis. Finally the third stage is to incorporate the designed process with the tested circuit in a layout that would produce the gate array as a GaAs integrated circuit.

  12. Gallium arsenide processing for gate array logic

    NASA Technical Reports Server (NTRS)

    Cole, Eric D.

    1989-01-01

    The development of a reliable and reproducible GaAs process was initiated for applications in gate array logic. Gallium Arsenide is an extremely important material for high speed electronic applications in both digital and analog circuits since its electron mobility is 3 to 5 times that of silicon, this allows for faster switching times for devices fabricated with it. Unfortunately GaAs is an extremely difficult material to process with respect to silicon and since it includes the arsenic component GaAs can be quite dangerous (toxic) especially during some heating steps. The first stage of the research was directed at developing a simple process to produce GaAs MESFETs. The MESFET (MEtal Semiconductor Field Effect Transistor) is the most useful, practical and simple active device which can be fabricated in GaAs. It utilizes an ohmic source and drain contact separated by a Schottky gate. The gate width is typically a few microns. Several process steps were required to produce a good working device including ion implantation, photolithography, thermal annealing, and metal deposition. A process was designed to reduce the total number of steps to a minimum so as to reduce possible errors. The first run produced no good devices. The problem occurred during an aluminum etch step while defining the gate contacts. It was found that the chemical etchant attacked the GaAs causing trenching and subsequent severing of the active gate region from the rest of the device. Thus all devices appeared as open circuits. This problem is being corrected and since it was the last step in the process correction should be successful. The second planned stage involves the circuit assembly of the discrete MESFETs into logic gates for test and analysis. Finally the third stage is to incorporate the designed process with the tested circuit in a layout that would produce the gate array as a GaAs integrated circuit.

  13. Cross-modal generality of the gating deficit.

    PubMed

    Edgar, J Christopher; Miller, Gregory A; Moses, Sandra N; Thoma, Robert J; Huang, Ming-Xiong; Hanlon, Faith M; Weisend, Michael P; Sherwood, Andrea; Bustillo, Juan; Adler, Larry E; Cañive, José M

    2005-05-01

    Auditory P50/M50 paired-click studies have established an association between schizophrenia and impaired sensory gating in the auditory modality. However, the presumed cross-modal generality of the gating deficit has received little study. The present study examined gating in area 3b of primary somatosensory cortex to evaluate patients' somatosensory gating at this first stage of cortical processing. One hundred twenty-two channels of magnetoencephalography (MEG) data were collected from 27 subjects with chronic schizophrenia and 21 controls during a somatosensory paired-pulse paradigm with a 75- or 500-ms interstimulus interval. M20 somatosensory responses were localized using magnetic source imaging, and a gating ratio was calculated. In a subset of these subjects, MEG was also done for the standard auditory paradigm to assess M50 gating. Patients showed abnormal auditory M50 gating but normal somatosensory M20 gating. Results argue against a cross-modal gating deficit in primary somatosensory cortex.

  14. Sliding-gate valve for use with abrasive materials

    DOEpatents

    Ayers, Jr., William J.; Carter, Charles R.; Griffith, Richard A.; Loomis, Richard B.; Notestein, John E.

    1985-01-01

    The invention is a flow and pressure-sealing valve for use with abrasive solids. The valve embodies special features which provide for long, reliable operating lifetimes in solids-handling service. The valve includes upper and lower transversely slidable gates, contained in separate chambers. The upper gate provides a solids-flow control function, whereas the lower gate provides a pressure-sealing function. The lower gate is supported by means for (a) lifting that gate into sealing engagement with its seat when the gate is in its open and closed positions and (b) lowering the gate out of contact with its seat to permit abrasion-free transit of the gate between its open and closed positions. When closed, the upper gate isolates the lower gate from the solids. Because of this shielding action, the sealing surface of the lower gate is not exposed to solids during transit or when it is being lifted or lowered. The chamber containing the lower gate normally is pressurized slightly, and a sweep gas is directed inwardly across the lower-gate sealing surface during the vertical translation of the gate.

  15. Hydraulics characteristics of tipping sediment flushing gate.

    PubMed

    Bong, C H J; Lau, T L; Ab Ghani, A

    2013-01-01

    This paper highlights a preliminary study on the potential of a tipping flush gate to be used in an open storm drain to remove sediment. The investigation was carried out by using a plasboard model of the tipping flush gate installed in a rectangular flume. A steady flow experiment was carried out to determine the discharge coefficients and also the outflow relationship of the tipping flush gate. The velocity produced by the gate at various distances downstream of the gate during flushing operation was measured using a flowmeter and the velocity at all the points was higher than the recommended self-cleansing design available in the literature. A preliminary experiment on the efficiency of flushing was conducted using uniform sediment with d50 sizes of 0.81, 1.53 and 4.78 mm. Results generally showed that the number of flushes required to totally remove the sediment from the initial position by a distance of 1 m increased by an average of 1.50 times as the sediment deposit bed thickness doubled. An equation relating the number of flushes required to totally remove the sediment bed for 1 m with the sediment bed deposit thickness was also developed for the current study.

  16. Cylindrical gate valve apparatus and method

    SciTech Connect

    Hynes, J. H.; Morrill, C. D.

    1985-04-30

    A safety valve is disclosed which may be installed on an offshore wellhead above the tubing head and below the Christmas tree. The valve has a housing with upper and lower vertical passages and a lateral housing passage. A cylindrical gate is disposed within the lateral passage and includes a ''T'' shaped passage therein. The gate may be moved laterally and angularly within the lateral passage. During completion or workover of the well, the gate is moved laterally until the upper and lower vertical passages are in full open communication to run drills, hangers or other large diameter devices into the well via a BOP which may be attached to the top of the housing. During normal production, the gate may be laterally moved into the intersection of the vertical and lateral passages and the small through head part of the ''T'' passage serves to provide a vertical flow path through the production bore which is sealed off from the larger upper and lower vertical passages. Flow through side outlets in the housing is possible through the base of the ''T'' passage. The gate may be angularly moved to have production to the lateral outlets via the head part of the ''T'' when the base part of the ''T'' is aligned with production tubing. Should the need arise, the valve may be angularly rotated to a position where the fluid flow path of the production tubing is completely shut in.

  17. Szilard engine reversibility as quantum gate function

    NASA Astrophysics Data System (ADS)

    Mihelic, F. Matthew

    2012-06-01

    A quantum gate is a logically and thermodynamically reversible situation that effects a unitary transformation of qubits of superimposed information, and essentially constitutes a situation for a reversible quantum decision. A quantum decision is a symmetry break, and the effect of the function of a Szilard engine is a symmetry break. A quantum gate is a situation in which a reversible quantum decision can be made, and so if a logically and thermodynamically reversible Szilard engine can be theoretically constructed then it would function as a quantum gate. While the traditionally theorized Szilard engine is not thermodynamically reversible, if one of the bounding walls of a Szilard engine were to be constructed out of the physical information by which it functions in such a manner as to make that information available to both sides of the wall simultaneously, then such a Szilard engine would be both logically and thermodynamically reversible, and thus capable of function as a quantum gate. A theoretical model of the special case of a reversible Szilard engine functioning as a quantum gate is presented and discussed, and since a quantum decision is made when the shutter of a Szilard engine closes, the coherence of linked reversible Szilard engines should be considered as a state during which all of the shutters of linked Szilard engines are open simultaneously.

  18. BK channels: multiple sensors, one activation gate.

    PubMed

    Yang, Huanghe; Zhang, Guohui; Cui, Jianmin

    2015-01-01

    Ion transport across cell membranes is essential to cell communication and signaling. Passive ion transport is mediated by ion channels, membrane proteins that create ion conducting pores across cell membrane to allow ion flux down electrochemical gradient. Under physiological conditions, majority of ion channel pores are not constitutively open. Instead, structural region(s) within these pores breaks the continuity of the aqueous ion pathway, thereby serves as activation gate(s) to control ions flow in and out. To achieve spatially and temporally regulated ion flux in cells, many ion channels have evolved sensors to detect various environmental stimuli or the metabolic states of the cell and trigger global conformational changes, thereby dynamically operate the opening and closing of their activation gate. The sensors of ion channels can be broadly categorized as chemical sensors and physical sensors to respond to chemical (such as neural transmitters, nucleotides and ions) and physical (such as voltage, mechanical force and temperature) signals, respectively. With the rapidly growing structural and functional information of different types of ion channels, it is now critical to understand how ion channel sensors dynamically control their gates at molecular and atomic level. The voltage and Ca(2+) activated BK channels, a K(+) channel with an electrical sensor and multiple chemical sensors, provide a unique model system for us to understand how physical and chemical energy synergistically operate its activation gate.

  19. Ion-dependent gating of kainate receptors.

    PubMed

    Bowie, Derek

    2010-01-01

    Ligand-gated ion channels are an important class of signalling protein that depend on small chemical neurotransmitters such as acetylcholine, l-glutamate, glycine and gamma-aminobutyrate for activation. Although numerous in number, neurotransmitter substances have always been thought to drive the receptor complex into the open state in much the same way and not rely substantially on other factors. However, recent work on kainate-type (KAR) ionotropic glutamate receptors (iGluRs) has identified an exception to this rule. Here, the activation process fails to occur unless external monovalent anions and cations are present. This absolute requirement of ions singles out KARs from all other ligand-gated ion channels, including closely related AMPA- and NMDA-type iGluR family members. The uniqueness of ion-dependent gating has earmarked this feature of KARs as a putative target for the development of selective ligands; a prospect all the more compelling with the recent elucidation of distinct anion and cation binding pockets. Despite these advances, much remains to be resolved. For example, it is still not clear how ion effects on KARs impacts glutamatergic transmission. I conclude by speculating that further analysis of ion-dependent gating may provide clues into how functionally diverse iGluRs families emerged by evolution. Consequently, ion-dependent gating of KARs looks set to continue to be a subject of topical inquiry well into the future.

  20. Bubbles, Gating, and Anesthetics in Ion Channels

    PubMed Central

    Roth, Roland; Gillespie, Dirk; Nonner, Wolfgang; Eisenberg, Robert E.

    2008-01-01

    We suggest that bubbles are the bistable hydrophobic gates responsible for the on-off transitions of single channel currents. In this view, many types of channels gate by the same physical mechanism—dewetting by capillary evaporation—but different types of channels use different sensors to modulate hydrophobic properties of the channel wall and thereby trigger and control bubbles and gating. Spontaneous emptying of channels has been seen in many simulations. Because of the physics involved, such phase transitions are inherently sensitive, unstable threshold phenomena that are difficult to simulate reproducibly and thus convincingly. We present a thermodynamic analysis of a bubble gate using morphometric density functional theory of classical (not quantum) mechanics. Thermodynamic analysis of phase transitions is generally more reproducible and less sensitive to details than simulations. Anesthetic actions of inert gases—and their interactions with hydrostatic pressure (e.g., nitrogen narcosis)—can be easily understood by actions on bubbles. A general theory of gas anesthesia may involve bubbles in channels. Only experiments can show whether, or when, or which channels actually use bubbles as hydrophobic gates: direct observation of bubbles in channels is needed. Existing experiments show thin gas layers on hydrophobic surfaces in water and suggest that bubbles nearly exist in bulk water. PMID:18234836

  1. Noisy signaling through promoter logic gates

    NASA Astrophysics Data System (ADS)

    Gerstung, Moritz; Timmer, Jens; Fleck, Christian

    2009-01-01

    We study the influence of noisy transcription factor signals on cis-regulatory promoter elements. These elements process the probability of binary binding events analogous to computer logic gates. At equilibrium, this probability is given by the so-called input function. We show that transcription factor noise causes deviations from the equilibrium value due to the nonlinearity of the input function. For a single binding site, the correction is always negative resulting in an occupancy below the mean-field level. Yet for more complex promoters it depends on the correlation of the transcription factor signals and the geometry of the input function. We present explicit solutions for the basic types of AND and OR gates. The correction size varies among these different types of gates and signal types, mainly being larger in AND gates and for correlated fluctuations. In all cases we find excellent agreement between the analytical results and numerical simulations. We also study the E. coli Lac operon as an example of an AND NOR gate. We present a consistent mathematical method that allows one to separate different sources of noise and quantifies their effect on promoter occupation. A surprising result of our analysis is that Poissonian molecular fluctuations, in contrast to external fluctuations, do no contribute to the correction.

  2. Active gated imaging for automotive safety applications

    NASA Astrophysics Data System (ADS)

    Grauer, Yoav; Sonn, Ezri

    2015-03-01

    The paper presents the Active Gated Imaging System (AGIS), in relation to the automotive field. AGIS is based on a fast gated-camera equipped with a unique Gated-CMOS sensor, and a pulsed Illuminator, synchronized in the time domain to record images of a certain range of interest which are then processed by computer vision real-time algorithms. In recent years we have learned the system parameters which are most beneficial to night-time driving in terms of; field of view, illumination profile, resolution and processing power. AGIS provides also day-time imaging with additional capabilities, which enhances computer vision safety applications. AGIS provides an excellent candidate for camera-based Advanced Driver Assistance Systems (ADAS) and the path for autonomous driving, in the future, based on its outstanding low/high light-level, harsh weather conditions capabilities and 3D potential growth capabilities.

  3. Transversal Clifford gates on folded surface codes

    NASA Astrophysics Data System (ADS)

    Moussa, Jonathan E.

    2016-10-01

    Surface and color codes are two forms of topological quantum error correction in two spatial dimensions with complementary properties. Surface codes have lower-depth error detection circuits and well-developed decoders to interpret and correct errors, while color codes have transversal Clifford gates and better code efficiency in the number of physical qubits needed to achieve a given code distance. A formal equivalence exists between color codes and folded surface codes, but it does not guarantee the transferability of any of these favorable properties. However, the equivalence does imply the existence of constant-depth circuit implementations of logical Clifford gates on folded surface codes. We achieve and improve this result by constructing two families of folded surface codes with transversal Clifford gates. This construction is presented generally for qudits of any dimension. The specific application of these codes to universal quantum computation based on qubit fusion is also discussed.

  4. Four-gate transistor analog multiplier circuit

    NASA Technical Reports Server (NTRS)

    Mojarradi, Mohammad M. (Inventor); Blalock, Benjamin (Inventor); Cristoloveanu, Sorin (Inventor); Chen, Suheng (Inventor); Akarvardar, Kerem (Inventor)

    2011-01-01

    A differential output analog multiplier circuit utilizing four G.sup.4-FETs, each source connected to a current source. The four G.sup.4-FETs may be grouped into two pairs of two G.sup.4-FETs each, where one pair has its drains connected to a load, and the other par has its drains connected to another load. The differential output voltage is taken at the two loads. In one embodiment, for each G.sup.4-FET, the first and second junction gates are each connected together, where a first input voltage is applied to the front gates of each pair, and a second input voltage is applied to the first junction gates of each pair. Other embodiments are described and claimed.

  5. The airport gate assignment problem: a survey.

    PubMed

    Bouras, Abdelghani; Ghaleb, Mageed A; Suryahatmaja, Umar S; Salem, Ahmed M

    2014-01-01

    The airport gate assignment problem (AGAP) is one of the most important problems operations managers face daily. Many researches have been done to solve this problem and tackle its complexity. The objective of the task is assigning each flight (aircraft) to an available gate while maximizing both conveniences to passengers and the operational efficiency of airport. This objective requires a solution that provides the ability to change and update the gate assignment data on a real time basis. In this paper, we survey the state of the art of these problems and the various methods to obtain the solution. Our survey covers both theoretical and real AGAP with the description of mathematical formulations and resolution methods such as exact algorithms, heuristic algorithms, and metaheuristic algorithms. We also provide a research trend that can inspire researchers about new problems in this area.

  6. The Airport Gate Assignment Problem: A Survey

    PubMed Central

    Ghaleb, Mageed A.; Salem, Ahmed M.

    2014-01-01

    The airport gate assignment problem (AGAP) is one of the most important problems operations managers face daily. Many researches have been done to solve this problem and tackle its complexity. The objective of the task is assigning each flight (aircraft) to an available gate while maximizing both conveniences to passengers and the operational efficiency of airport. This objective requires a solution that provides the ability to change and update the gate assignment data on a real time basis. In this paper, we survey the state of the art of these problems and the various methods to obtain the solution. Our survey covers both theoretical and real AGAP with the description of mathematical formulations and resolution methods such as exact algorithms, heuristic algorithms, and metaheuristic algorithms. We also provide a research trend that can inspire researchers about new problems in this area. PMID:25506074

  7. Transversal Clifford gates on folded surface codes

    SciTech Connect

    Moussa, Jonathan E.

    2016-10-12

    Surface and color codes are two forms of topological quantum error correction in two spatial dimensions with complementary properties. Surface codes have lower-depth error detection circuits and well-developed decoders to interpret and correct errors, while color codes have transversal Clifford gates and better code efficiency in the number of physical qubits needed to achieve a given code distance. A formal equivalence exists between color codes and folded surface codes, but it does not guarantee the transferability of any of these favorable properties. However, the equivalence does imply the existence of constant-depth circuit implementations of logical Clifford gates on folded surface codes. We achieve and improve this result by constructing two families of folded surface codes with transversal Clifford gates. This construction is presented generally for qudits of any dimension. Lastly, the specific application of these codes to universal quantum computation based on qubit fusion is also discussed.

  8. Transversal Clifford gates on folded surface codes

    DOE PAGES

    Moussa, Jonathan E.

    2016-10-12

    Surface and color codes are two forms of topological quantum error correction in two spatial dimensions with complementary properties. Surface codes have lower-depth error detection circuits and well-developed decoders to interpret and correct errors, while color codes have transversal Clifford gates and better code efficiency in the number of physical qubits needed to achieve a given code distance. A formal equivalence exists between color codes and folded surface codes, but it does not guarantee the transferability of any of these favorable properties. However, the equivalence does imply the existence of constant-depth circuit implementations of logical Clifford gates on folded surfacemore » codes. We achieve and improve this result by constructing two families of folded surface codes with transversal Clifford gates. This construction is presented generally for qudits of any dimension. Lastly, the specific application of these codes to universal quantum computation based on qubit fusion is also discussed.« less

  9. Maritime target identification in gated viewing imagery

    NASA Astrophysics Data System (ADS)

    Hammer, Marcus; Hebel, Marcus; Arens, Michael

    2015-10-01

    The growing interest in unmanned surface vehicles, accident avoidance for naval vessels and automated maritime surveillance leads to a growing need for automatic detection, classification and pose estimation of maritime objects in medium and long ranges. Laser radar imagery is a well proven tool for near to medium range, but up to now for higher distances neither the sensor range nor the sensor resolution was satisfying. As a result of the mentioned limitations of laser radar imagery the potential of laser illuminated gated viewing for automated classification and pose estimation was investigated. The paper presents new techniques for segmentation, pose estimation and model-based identification of naval vessels in gated viewing imagery in comparison with the corresponding results of long range data acquired with a focal plane array laser radar system. The pose estimation in the gated viewing data is directly connected with the model-based identification which makes use of the outline of the object. By setting a sufficient narrow gate, the distance gap between the upper part of the ship and the background leads to an automatic segmentation. By setting the gate the distance to the object is roughly known. With this distance and the imaging properties of the camera, the width of the object perpendicular to the line of sight can be calculated. For each ship in the model library a set of possible 2D appearances in the known distance is calculated and the resulting contours are compared with the measured 2D outline. The result is a match error for each reasonable orientation of each model of the library. The result gained from the gated viewing data is compared with the results of target identification by laser radar imagery of the same maritime objects.

  10. Operational life prediction on gating image intensifier

    NASA Astrophysics Data System (ADS)

    Dong, Yu-hui; Shen, Zhi-guo; Li, Zhong-li

    2009-07-01

    Operational life is one of the important parameters to evaluate second and super second generation image intensifiers. It can be used not only to monitor manufacturing technique in product line, then the technology on photocathode processing, MCP degassing and MCP producing can be adjusted promptly, but also to eliminate the image intensifiers which have hidden risk on operational life as early as possible. Recently gating image intensifiers are used widely, method to estimate the operational life of gating image intensifier related to its practical operate mode and working condition need to be established urgently. The least square method to analyze the operational life test data in product line was introduced in this paper. Now the data can be analyzed with convenient statistic analyze function on Excel. Using "worksheet function" and "chart wizard" and "data analysis" on Excel to do the least square method calculation, spreadsheets are established to do complex data calculation with worksheet functions. Based on them, formulas to monitor the technology parameters were derived, and the conclusion that the operational life was only related to the decrease slope of photocathode exponential fit curve was made. The decrease slope of photocathode sensitivity exponential fit curve and the decrease percent of the exponential fit photocathode sensitivity can be used to evaluate the qualification of the operational life rapidly. The mathematic models for operational life prediction on image intensifier and gating image intensifier are established respectively based on the acceptable values of the decrease percent of the exponential fit photocathode sensitivity and the expecting signal to noise ratio. The equations predicting the operational life related to duty cycle and input light level on gating image intensifier were derived, and the relationship between them were discussed too. The theory foundation were made herein, so the user can select proper gating image

  11. Ultralow turnoff loss dual-gate SOI LIGBT with trench gate barrier and carrier stored layer

    NASA Astrophysics Data System (ADS)

    He, Yi-Tao; Qiao, Ming; Zhang, Bo

    2016-12-01

    A novel ultralow turnoff loss dual-gate silicon-on-insulator (SOI) lateral insulated gate bipolar transistor (LIGBT) is proposed. The proposed SOI LIGBT features an extra trench gate inserted between the p-well and n-drift, and an n-type carrier stored (CS) layer beneath the p-well. In the on-state, the extra trench gate acts as a barrier, which increases the carrier density at the cathode side of n-drift region, resulting in a decrease of the on-state voltage drop (Von). In the off-state, due to the uniform carrier distribution and the assisted depletion effect induced by the extra trench gate, large number of carriers can be removed at the initial turnoff process, contributing to a low turnoff loss (Eoff). Moreover, owing to the dual-gate field plates and CS layer, the carrier density beneath the p-well can greatly increase, which further improves the tradeoff between Eoff and Von. Simulation results show that Eoff of the proposed SOI LIGBT can decrease by 77% compared with the conventional trench gate SOI LIGBT at the same Von of 1.1 V. Project supported by the National Natural Science Foundation of China (Grant Nos. 61376080 and 61674027) and the Natural Science Foundation of Guangdong Province, China (Grant Nos. 2014A030313736 and 2016A030311022).

  12. Lipid-dependent gating of a voltage-gated potassium channel

    PubMed Central

    Zheng, Hui; Liu, Weiran; Anderson, Lingyan Y.; Jiang, Qiu-Xing

    2011-01-01

    Recent studies hypothesized that phospholipids stabilize two voltage-sensing arginine residues of certain voltage-gated potassium channels in activated conformations. It remains unclear how lipids directly affect these channels. Here, by examining the conformations of the KvAP in different lipids, we showed that without voltage change, the voltage-sensor domains switched from the activated to the resting state when their surrounding lipids were changed from phospholipids to nonphospholipids. Such lipid-determined conformational change was coupled to the ion-conducting pore, suggesting that parallel to voltage gating, the channel is gated by its annular lipids. Our measurements recognized that the energetic cost of lipid-dependent gating approaches that of voltage gating, but kinetically it appears much slower. Our data support that a channel and its surrounding lipids together constitute a functional unit, and natural nonphospholipids such as cholesterol should exert strong effects on voltage-gated channels. Our first observation of lipid-dependent gating may have general implications to other membrane proteins. PMID:21427721

  13. Gating of the designed trimeric/tetrameric voltage-gated H+ channel

    PubMed Central

    Fujiwara, Yuichiro; Kurokawa, Tatsuki; Takeshita, Kohei; Nakagawa, Atsushi; Larsson, H Peter; Okamura, Yasushi

    2013-01-01

    The voltage-gated H+ channel functions as a dimer, a configuration that is different from standard tetrameric voltage-gated channels. Each channel protomer has its own permeation pathway. The C-terminal coiled-coil domain has been shown to be necessary for both dimerization and cooperative gating in the two channel protomers. Here we report the gating cooperativity in trimeric and tetrameric Hv channels engineered by altering the hydrophobic core sequence of the coiled-coil assembly domain. Trimeric and tetrameric channels exhibited more rapid and less sigmoidal kinetics of activation of H+ permeation than dimeric channels, suggesting that some channel protomers in trimers and tetramers failed to produce gating cooperativity observed in wild-type dimers. Multimerization of trimer and tetramer channels were confirmed by the biochemical analysis of proteins, including crystallography. These findings indicate that the voltage-gated H+ channel is optimally designed as a dimeric channel on a solid foundation of the sequence pattern of the coiled-coil core, with efficient cooperative gating that ensures sustained and steep voltage-dependent H+ conductance in blood cells. PMID:23165764

  14. Coupling between Voltage Sensors and Activation Gate in Voltage-gated K+ Channels

    PubMed Central

    Lu, Zhe; Klem, Angela M.; Ramu, Yajamana

    2002-01-01

    Current through voltage-gated K+ channels underlies the action potential encoding the electrical signal in excitable cells. The four subunits of a voltage-gated K+ channel each have six transmembrane segments (S1–S6), whereas some other K+ channels, such as eukaryotic inward rectifier K+ channels and the prokaryotic KcsA channel, have only two transmembrane segments (M1 and M2). A voltage-gated K+ channel is formed by an ion-pore module (S5–S6, equivalent to M1–M2) and the surrounding voltage-sensing modules. The S4 segments are the primary voltage sensors while the intracellular activation gate is located near the COOH-terminal end of S6, although the coupling mechanism between them remains unknown. In the present study, we found that two short, complementary sequences in voltage-gated K+ channels are essential for coupling the voltage sensors to the intracellular activation gate. One sequence is the so called S4–S5 linker distal to the voltage-sensing S4, while the other is around the COOH-terminal end of S6, a region containing the actual gate-forming residues. PMID:12407078

  15. Cyclic groups and quantum logic gates

    NASA Astrophysics Data System (ADS)

    Pourkia, Arash; Batle, J.; Raymond Ooi, C. H.

    2016-10-01

    We present a formula for an infinite number of universal quantum logic gates, which are 4 by 4 unitary solutions to the Yang-Baxter (Y-B) equation. We obtain this family from a certain representation of the cyclic group of order n. We then show that this discrete family, parametrized by integers n, is in fact, a small sub-class of a larger continuous family, parametrized by real numbers θ, of universal quantum gates. We discuss the corresponding Yang-Baxterization and related symmetries in the concomitant Hamiltonian.

  16. Fidelity of adiabatic holonomic quantum gates

    NASA Astrophysics Data System (ADS)

    Malinovsky, Vladimir; Rudin, Sergey

    2016-05-01

    During last few years non-Abelian geometric phases are attracting increasing interest due to possible experimental applications in quantum computation. Here we discuss universal set of holonomic quantum gates using the geometric phase that the qubit wave function acquires after a cyclic evolution. The proposed scheme utilizes ultrafast pulses and provides a possibility to substantially suppress transient population of the ancillary states. Fidelity of the holonomic quantum gates in the presence of dephasing and dissipation is discussed. Example of electron spin qubit system in the InGaN/GaN, GaN/AlN quantum dot is considered in details.

  17. Gate dependent electronic Raman scattering in graphene

    NASA Astrophysics Data System (ADS)

    Riccardi, E.; Méasson, M.-A.; Kazayous, M.; Sacuto, A.; Gallais, Y.; Spectroscopy Of Quasi-Particles (Squap) Team

    We report the direct observation of polarization resolved electronic Raman scattering in a gated monolayer graphene device. The evolution of the electronic Raman scattering spectra with gate voltage and its polarization dependence are in full agreement with theoretical expectations for non-resonant Raman processes involving interband electron-hole excitations across the Dirac cone. We further show that the spectral dependence of the electronic Raman scattering signal can be simply described by the dynamical polarizability of graphene in the long wavelength limit. The possibility to directly observe Dirac fermion excitations in graphene opens the way to promising Raman investigations of electronic properties of graphene and other 2D materials.

  18. Gate dependent electronic Raman scattering in graphene

    NASA Astrophysics Data System (ADS)

    Riccardi, E.; Méasson, M.-A.; Kazayous, M.; Sacuto, A.; Gallais, Y.; Spectroscopy Of Quasi-Particles (Squap) Team

    We report the direct observation of polarization resolved electronic Raman scattering in a gated monolayer graphene device. The evolution of the electronic Raman scattering spectra with gate voltage and its polarization dependence are in full agreement with theoretical expectations for non-resonant Raman processes involving interband electron-hole excitations across the Dirac cone [1]. We further show that the spectral dependence of the electronic Raman scattering signal can be simply described by the dynamical polarizability of graphene in the long wavelength limit [2]. The possibility to directly observe Dirac fermion excitations in graphene opens the way to promising Raman investigations of electronic properties of graphene and other 2D materials.

  19. Optimizing the fast Rydberg quantum gate

    SciTech Connect

    Safronova, M.S.; Williams, Carl J.; Clark, Charles W.

    2003-04-01

    The fast phase gate scheme, in which the qubits are atoms confined in sites of an optical lattice, and gate operations are mediated by excitation of Rydberg states, was proposed by Jaksch et al. [Phys. Rev. Lett. 85, 2208 (2000)]. A potential source of decoherence in this system derives from motional heating, which occurs if the ground and Rydberg states of the atom move in different optical lattice potentials. We propose to minimize this effect by choosing the lattice photon frequency {omega}, so that the ground and Rydberg states have the same frequency-dependent polarizability {alpha}({omega}). The results are presented for the case of Rb.

  20. Gated IR Images of Shocked Surfaces

    SciTech Connect

    S. S. Lutz; W. D. Turley; P. M. Rightley; L. E. Primas

    2001-06-01

    Gated infrared (IR) images have been taken of a series of shocked surface geometries in tin. Metal coupons machined with steps and flats were mounted directly to the high explosive. The explosive was point-initiated and 500-ns to 1-microsecond-wide gated images of the target were taken immediately following shock breakout using a Santa Barbara Focalplane InSb camera (SBF-134). Spatial distributions of surface radiance were extracted from the images of the shocked samples and found to be non-single-valued. Several geometries were modeled using CTH, a two-dimensional Eulerian hydrocode.

  1. Gated IR images of shocked surfaces.

    SciTech Connect

    Lutz, S. S.; Turley, W. D.; Rightley, P. M.; Primas, L. E.

    2001-01-01

    Gated infrared (IR) images have been taken of a series of shocked surface geometries in tin. Metal coupons machined with steps and flats were mounted directly to the high explosive. The explosive was point-initiated and 500-ns to 1-microsecond-wide gated images of the target were taken immediately following shock breakout using a Santa Barbara Focalplane InSb camera (SBF-134). Spatial distributions of surface radiance were extracted from the images of the shocked samples and found to be non-single-valued. Several geometries were modeled using CTH, a two-dimensional Eulerian hydrocode.

  2. Coherent spaces, Boolean rings and quantum gates

    NASA Astrophysics Data System (ADS)

    Vourdas, A.

    2016-10-01

    Coherent spaces spanned by a finite number of coherent states, are introduced. Their coherence properties are studied, using the Dirac contour representation. It is shown that the corresponding projectors resolve the identity, and that they transform into projectors of the same type, under displacement transformations, and also under time evolution. The set of these spaces, with the logical OR and AND operations is a distributive lattice, and with the logical XOR and AND operations is a Boolean ring (Stone's formalism). Applications of this Boolean ring into classical CNOT gates with n-ary variables, and also quantum CNOT gates with coherent states, are discussed.

  3. Ultrafast quantum gates in circuit QED.

    PubMed

    Romero, G; Ballester, D; Wang, Y M; Scarani, V; Solano, E

    2012-03-23

    We present a method to implement ultrafast two-qubit gates valid for the ultrastrong coupling and deep strong coupling regimes of light-matter interaction, considering state-of-the-art circuit quantum electrodynamics technology. Our proposal includes a suitable qubit architecture and is based on a four-step sequential displacement of the intracavity field, operating at a time proportional to the inverse of the resonator frequency. Through ab initio calculations, we show that these quantum gates can be performed at subnanosecond time scales while keeping a fidelity above 99%.

  4. Gate-Controlled WSe2 Transistors Using a Buried Triple-Gate Structure

    NASA Astrophysics Data System (ADS)

    Müller, M. R.; Salazar, R.; Fathipour, S.; Xu, H.; Kallis, K.; Künzelmann, U.; Seabaugh, A.; Appenzeller, J.; Knoch, J.

    2016-11-01

    In the present paper, we show tungsten diselenide (WSe2) devices that can be tuned to operate as n-type and p-type field-effect transistors (FETs) as well as band-to-band tunnel transistors on the same flake. Source, channel, and drain areas of the WSe2 flake are adjusted, using buried triple-gate substrates with three independently controllable gates. The device characteristics found in the tunnel transistor configuration are determined by the particular geometry of the buried triple-gate structure, consistent with a simple estimation of the expected off-state behavior.

  5. Determination of prospective displacement-based gate threshold for respiratory-gated radiation delivery from retrospective phase-based gate threshold selected at 4D CT simulation

    SciTech Connect

    Vedam, S.; Archambault, L.; Starkschall, G.; Mohan, R.; Beddar, S.

    2007-11-15

    Four-dimensional (4D) computed tomography (CT) imaging has found increasing importance in the localization of tumor and surrounding normal structures throughout the respiratory cycle. Based on such tumor motion information, it is possible to identify the appropriate phase interval for respiratory gated treatment planning and delivery. Such a gating phase interval is determined retrospectively based on tumor motion from internal tumor displacement. However, respiratory-gated treatment is delivered prospectively based on motion determined predominantly from an external monitor. Therefore, the simulation gate threshold determined from the retrospective phase interval selected for gating at 4D CT simulation may not correspond to the delivery gate threshold that is determined from the prospective external monitor displacement at treatment delivery. The purpose of the present work is to establish a relationship between the thresholds for respiratory gating determined at CT simulation and treatment delivery, respectively. One hundred fifty external respiratory motion traces, from 90 patients, with and without audio-visual biofeedback, are analyzed. Two respiratory phase intervals, 40%-60% and 30%-70%, are chosen for respiratory gating from the 4D CT-derived tumor motion trajectory. From residual tumor displacements within each such gating phase interval, a simulation gate threshold is defined based on (a) the average and (b) the maximum respiratory displacement within the phase interval. The duty cycle for prospective gated delivery is estimated from the proportion of external monitor displacement data points within both the selected phase interval and the simulation gate threshold. The delivery gate threshold is then determined iteratively to match the above determined duty cycle. The magnitude of the difference between such gate thresholds determined at simulation and treatment delivery is quantified in each case. Phantom motion tests yielded coincidence of simulation

  6. 6. DETAIL VIEW OF TAINTER GATE PIER AND NONSUBMERSIBLE TAINTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. DETAIL VIEW OF TAINTER GATE PIER AND NON-SUBMERSIBLE TAINTER GATE, SHOWING MAIN LOCK IN BACKGROUND, LOOKING NORTH (UPSTREAM) - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  7. DOWNSTREAM LOCK GATE DETAIL VIEW WITH DOG HOUSE. NOTE CONTROL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DOWNSTREAM LOCK GATE DETAIL VIEW WITH DOG HOUSE. NOTE CONTROL ARM AND GEAR FOR GATE. LOOKING NORTHWEST. - Illinois Waterway, Dresden Island Lock and Dam , 7521 North Lock Road, Channahon, Will County, IL

  8. UPSTREAM LOCK GATE DETAIL AND DOG HOUSE. NOTE ARM AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    UPSTREAM LOCK GATE DETAIL AND DOG HOUSE. NOTE ARM AND GEARING FOR CONTROLLING LOCK GATE. LOOKING WEST SOUTHWEST. - Illinois Waterway, Brandon Road Lock and Dam , 1100 Brandon Road, Joliet, Will County, IL

  9. 14. DETAILS OF GATE OPERATING MECHANISM, SHOWING RACK SECTION, CUT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. DETAILS OF GATE OPERATING MECHANISM, SHOWING RACK SECTION, CUT TEETH, CAST TEETH, GATE PINION (1907) - Nine Mile Hydroelectric Development, Powerhouse, State Highway 291 along Spokane River, Nine Mile Falls, Spokane County, WA

  10. 11. DETAIL OF UPSTREAM FACE OF SLUICE GATE CONTROLS FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. DETAIL OF UPSTREAM FACE OF SLUICE GATE CONTROLS FROM CATWALK, SHOWING GATE LIFTING GEARS (TOP) AND GEAR SHAFTS (BOTTOM). VIEW TO SOUTHWEST. - Boise Project, Boise River Diversion Dam, Across Boise River, Boise, Ada County, ID

  11. NORTH GATE AT 11TH AVENUE (490 NORTH & 900 EAST), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTH GATE AT 11TH AVENUE (490 NORTH & 900 EAST), SALT LAKE CITY, UT. VIEW LOOKING SOUTH AT CEMETERY'S NORTH GATE (WPA PROJECT, 1938-1941). - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT

  12. WEST PIER OF NORTH GATE (490 NORTH & 900 EAST), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    WEST PIER OF NORTH GATE (490 NORTH & 900 EAST), SALT LAKE CITY, UT. VIEW LOOKING SOUTH AT THE WEST PIER OF THE CEMETERY'S NORTH GATE. - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT

  13. 5. DETAIL VIEW OF RADIAN GATE (LEFT, IN RAISED POSITION) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DETAIL VIEW OF RADIAN GATE (LEFT, IN RAISED POSITION) AND HAND- OPERATED GATE HOISTS (RIGHT), LOOKING WEST - Upper Souris National Wildlife Refuge, Dam 87, Souris River Basin, Foxholm, Surrey (England), ND

  14. Micromachined mold-type double-gated metal field emitters

    NASA Astrophysics Data System (ADS)

    Lee, Yongjae; Kang, Seokho; Chun, Kukjin

    1997-12-01

    Electron field emitters with double gates were fabricated using micromachining technology and the effect of the electric potential of the focusing gate (or second gate) was experimentally evaluated. The molybdenum field emission tip was made by filling a cusplike mold formed when a conformal film was deposited on the hole-trench that had been patterned on stacked metals and dielectric layers. The hole-trench was patterned by electron beam lithography and reactive ion etching. Each field emitter has a 0960-1317/7/4/009/img1 diameter extraction gate (or first gate) and a 0960-1317/7/4/009/img2 diameter focusing gate (or second gate). To make a path for the emitted electrons, silicon bulk was etched anisotropically in KOH and EDP (ethylene-diamine pyrocatechol) solution successively. The I - V characteristics and anode current change due to the focusing gate potential were measured.

  15. 2. ALABAMA GATES LOOKING SOUTHEAST ALONG LINED CHANNEL, NOTE CHEMICAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. ALABAMA GATES LOOKING SOUTHEAST ALONG LINED CHANNEL, NOTE CHEMICAL PURIFICATION TANK IN DISTANCE FOR KEEPING DOWN GROWTH OF ALGAE - Los Angeles Aqueduct, Alabama Gates, Los Angeles, Los Angeles County, CA

  16. 38. VIEW OF AUXILIARY LOCK MITER GATE, WITH MAIN LOCK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. VIEW OF AUXILIARY LOCK MITER GATE, WITH MAIN LOCK UPSTREAM MITER GATE AND UPSTREAM GUIDEWALL IN BACKGROUND, LOOKING WEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  17. Washington Water Power Spokane River Upper Falls Hydroelectric Development, Gates ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Washington Water Power Spokane River Upper Falls Hydroelectric Development, Gates & Gate-Lifting Mechanisms, Spokane River, approximately 0.5 mile northeast of intersection of Spokane Falls Boulevard & Post Street, Spokane, Spokane County, WA

  18. Improved Classical Simulation of Quantum Circuits Dominated by Clifford Gates.

    PubMed

    Bravyi, Sergey; Gosset, David

    2016-06-24

    We present a new algorithm for classical simulation of quantum circuits over the Clifford+T gate set. The runtime of the algorithm is polynomial in the number of qubits and the number of Clifford gates in the circuit but exponential in the number of T gates. The exponential scaling is sufficiently mild that the algorithm can be used in practice to simulate medium-sized quantum circuits dominated by Clifford gates. The first demonstrations of fault-tolerant quantum circuits based on 2D topological codes are likely to be dominated by Clifford gates due to a high implementation cost associated with logical T gates. Thus our algorithm may serve as a verification tool for near-term quantum computers which cannot in practice be simulated by other means. To demonstrate the power of the new method, we performed a classical simulation of a hidden shift quantum algorithm with 40 qubits, a few hundred Clifford gates, and nearly 50 T gates.

  19. 13. WATER BEING RELEASED THRU 4 X 4 GATE AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. WATER BEING RELEASED THRU 4 X 4 GATE AT DAM 96 TO PROVIDE WATER CUSHION PRIOR TO OPENING RADIAL GATE - Upper Souris National Wildlife Refuge, Dam 96, Souris River Basin, Foxholm, Surrey (England), ND

  20. 14. DETAIL VIEW OF BRONZE ROLLER GATE GAUGE, LOOKING SOUTHEAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. DETAIL VIEW OF BRONZE ROLLER GATE GAUGE, LOOKING SOUTHEAST INSIDE ROLLER GATE OPERATING MACHINERY HOUSE - Upper Mississippi River Nine-Foot Channel Project, Lock & Dam No. 25, Cap au Gris, Lincoln County, MO

  1. 5. DETAIL VIEW OF DAM, SHOWING ROLLER AND TAINTER GATES, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DETAIL VIEW OF DAM, SHOWING ROLLER AND TAINTER GATES, GATE PIERS, HEADHOUSES AND DAM BRIDGE, LOOKING NORTHWEST, UPSTREAM - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  2. 1. UPPER SEGMENT OF SPILLWAY CHANNEL, DRUM GATES ALONG SIDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. UPPER SEGMENT OF SPILLWAY CHANNEL, DRUM GATES ALONG SIDE OF CHANNEL, LOOKING SOUTH (up the channel) - Tieton Dam, Spillway & Drum Gates, South & East side of State Highway 12, Naches, Yakima County, WA

  3. 4. SPILLWAY DRUM GATES AND CHANNEL, LOOKING NORTHEAST (upstream face ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. SPILLWAY DRUM GATES AND CHANNEL, LOOKING NORTHEAST (upstream face and Control House in background) - Tieton Dam, Spillway & Drum Gates, South & East side of State Highway 12, Naches, Yakima County, WA

  4. Plan and section of diversion gates, and plan and elevations ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Plan and section of diversion gates, and plan and elevations of gate controller - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

  5. 10. UPSTREAM SIDE OF UPPER MITER GATES SHOWING STOWED LEFT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. UPSTREAM SIDE OF UPPER MITER GATES SHOWING STOWED LEFT WING OF UPPER GUARD GATE (FAR LEFT). VIEW TO NORTHWEST. - Starved Rock Locks & Dam, Illinois Waterway River mile 231, Peru, La Salle County, IL

  6. 15. OVERALL VIEW OF UPSTREAM FACE OF LIFT GATE SECTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. OVERALL VIEW OF UPSTREAM FACE OF LIFT GATE SECTION WITH TAINTER GATE SECTION OF SPILLWAY TO THE LEFT. VIEW TO SOUTHWEST. - Starved Rock Locks & Dam, Illinois Waterway River mile 231, Peru, La Salle County, IL

  7. Gate sequence for continuous variable one-way quantum computation

    PubMed Central

    Su, Xiaolong; Hao, Shuhong; Deng, Xiaowei; Ma, Lingyu; Wang, Meihong; Jia, Xiaojun; Xie, Changde; Peng, Kunchi

    2013-01-01

    Measurement-based one-way quantum computation using cluster states as resources provides an efficient model to perform computation and information processing of quantum codes. Arbitrary Gaussian quantum computation can be implemented sufficiently by long single-mode and two-mode gate sequences. However, continuous variable gate sequences have not been realized so far due to an absence of cluster states larger than four submodes. Here we present the first continuous variable gate sequence consisting of a single-mode squeezing gate and a two-mode controlled-phase gate based on a six-mode cluster state. The quantum property of this gate sequence is confirmed by the fidelities and the quantum entanglement of two output modes, which depend on both the squeezing and controlled-phase gates. The experiment demonstrates the feasibility of implementing Gaussian quantum computation by means of accessible gate sequences.

  8. 5. VIEW OF UPRIGHT OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF UPRIGHT OUTLET GATE WHEEL, STEM AND STEM GUIDE (HARDESTY CAST IRON RECTANGULAR SLIDE GATE), LOOKING SOUTHWEST - High Mountain Dams in Bonneville Unit, Lost Lake Dam, Kamas, Summit County, UT

  9. 6. VIEW SHOWING INCLINED OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW SHOWING INCLINED OUTLET GATE WHEEL, STEM AND STEM GUIDE (18' HARDESTY GATE), LOOKING SOUTHEAST - High Mountain Dams in Bonneville Unit, Long Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  10. 5. VIEW OF UPRIGHT OUTLET GATE, STEM, STEM GUIDE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF UPRIGHT OUTLET GATE, STEM, STEM GUIDE AND WHEEL (10' HARDESTY CAST IRON VERTICAL LIFT GATE), LOOKING WEST - High Mountain Dams in Bonneville Unit, Weir Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  11. 4. VIEW OF INCLINED OUTLET GATE, STEM, STEM GUIDE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW OF INCLINED OUTLET GATE, STEM, STEM GUIDE AND WHEEL (10' HARDESTY VERTICAL LIFT GATE), LOOKING NORTHWEST - High Mountain Dams in Bonneville Unit, Pot Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  12. 7. VIEW OF UPRIGHT OUTLET GATE, WHEEL STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF UPRIGHT OUTLET GATE, WHEEL STEM AND STEM GUIDE (14' DIAMETER CIRCULAR CALCO CAST IRON SLIDE GATE), LOOKING SOUTHEAST - High Mountain Dams in Bonneville Unit, Fire Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  13. 7. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM GUIDE (15' HARDESTY MODEL 115 GATE), LOOKING NORTHWEST - High Mountain Dams in Bonneville Unit, Marjorie Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  14. 4. VIEW NORTHWEST, INTERIOR OF GATEHOUSE, SHOWING ROW OF GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW NORTHWEST, INTERIOR OF GATEHOUSE, SHOWING ROW OF GATE OPERATING MECHANISMS; HEIGHT OF STEMS INDICATES FOREGROUND GATE IS OPEN - Norwich Water Power Company, Headgates, West bank of Shetucket River opposite Fourteenth Street, Greenville section, Norwich, New London County, CT

  15. 5. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM GUIDE, (12' DIAMETER HARDESTY MODEL 112 CIRCULAR GATE), LOOKING NORTHEAST - High Mountain Dams in Bonneville Unit, Island Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  16. 7. South gate to Migel Estate and Farm along original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. South gate to Migel Estate and Farm along original alignment. Gate located at intersection of Orange Turnpike and Harriman Heights Road. View looking north. - Orange Turnpike, Parallel to new Orange Turnpike, Monroe, Orange County, NY

  17. 19. STAIRWAY TO TAINTER GATE SECTION OF SPILLWAY, SHOWING STEAM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. STAIRWAY TO TAINTER GATE SECTION OF SPILLWAY, SHOWING STEAM PIPES EMERGING FROM BOILERHOUSE (RIGHT) AND CONCRETE TAINTER GATE COUNTER WEIGHTS (BACKGROUND RIGHT). VIEW TO SOUTH. - Starved Rock Locks & Dam, Illinois Waterway River mile 231, Peru, La Salle County, IL

  18. 12. DETAIL VIEW OF CIRCULAR BRONZE ROLLER GATE POSITION GAUGE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. DETAIL VIEW OF CIRCULAR BRONZE ROLLER GATE POSITION GAUGE, ROLLER GATE PIER HOUSE, TYPE 2A, DAM - Mississippi River 9-Foot Channel Project, Lock & Dam No. 11, Upper Mississippi River, Dubuque, Dubuque County, IA

  19. Corticostriatal output gating during selection from working memory.

    PubMed

    Chatham, Christopher H; Frank, Michael J; Badre, David

    2014-02-19

    Convergent evidence suggests that corticostriatal interactions act as a gate to select the input to working memory (WM). However, not all information in WM is relevant for behavior simultaneously. For this reason, a second "output gate" might advantageously govern which contents of WM influence behavior. Here, we test whether frontostriatal circuits previously implicated in input gating also support output gating during selection from WM. fMRI of a hierarchical rule task with dissociable input and output gating demands demonstrated greater lateral prefrontal cortex (PFC) recruitment and frontostriatal connectivity during output gating. Moreover, PFC and striatum correlated with distinct behavioral profiles. Whereas PFC recruitment correlated with mean efficiency of selection from WM, striatal recruitment and frontostriatal interactions correlated with its reliability, as though such dynamics stochastically gate WM's output. These results support the output gating hypothesis, suggesting that contextual representations in PFC influence striatum to select which information in WM drives responding.

  20. Reliability study of refractory gate gallium arsenide MESFETS

    NASA Technical Reports Server (NTRS)

    Yin, J. C. W.; Portnoy, W. M.

    1981-01-01

    Refractory gate MESFET's were fabricated as an alternative to aluminum gate devices, which have been found to be unreliable as RF power amplifiers. In order to determine the reliability of the new structures, statistics of failure and information about mechanisms of failure in refractory gate MESFET's are given. Test transistors were stressed under conditions of high temperature and forward gate current to enhance failure. Results of work at 150 C and 275 C are reported.

  1. Self-gated fat-suppressed cardiac cine MRI.

    PubMed

    Ingle, R Reeve; Santos, Juan M; Overall, William R; McConnell, Michael V; Hu, Bob S; Nishimura, Dwight G

    2015-05-01

    To develop a self-gated alternating repetition time balanced steady-state free precession (ATR-SSFP) pulse sequence for fat-suppressed cardiac cine imaging. Cardiac gating is computed retrospectively using acquired magnetic resonance self-gating data, enabling cine imaging without the need for electrocardiogram (ECG) gating. Modification of the slice-select rephasing gradients of an ATR-SSFP sequence enables the acquisition of a one-dimensional self-gating readout during the unused short repetition time (TR). Self-gating readouts are acquired during every TR of segmented, breath-held cardiac scans. A template-matching algorithm is designed to compute cardiac trigger points from the self-gating signals, and these trigger points are used for retrospective cine reconstruction. The proposed approach is compared with ECG-gated ATR-SSFP and balanced steady-state free precession in 10 volunteers and five patients. The difference of ECG and self-gating trigger times has a variability of 13 ± 11 ms (mean ± SD). Qualitative reviewer scoring and ranking indicate no statistically significant differences (P > 0.05) between self-gated and ECG-gated ATR-SSFP images. Quantitative blood-myocardial border sharpness is not significantly different among self-gated ATR-SSFP ( 0.61±0.15 mm -1), ECG-gated ATR-SSFP ( 0.61±0.15 mm -1), or conventional ECG-gated balanced steady-state free precession cine MRI ( 0.59±0.15 mm -1). The proposed self-gated ATR-SSFP sequence enables fat-suppressed cardiac cine imaging at 1.5 T without the need for ECG gating and without decreasing the imaging efficiency of ATR-SSFP. © 2014 Wiley Periodicals, Inc.

  2. Self-Gated Fat-Suppressed Cardiac Cine MRI

    PubMed Central

    Ingle, R. Reeve; Santos, Juan M.; Overall, William R.; McConnell, Michael V.; Hu, Bob S.; Nishimura, Dwight G.

    2014-01-01

    Purpose To develop a self-gated alternating repetition time balanced steady-state free precession (ATR-SSFP) pulse sequence for fat-suppressed cardiac cine imaging. Methods Cardiac gating is computed retrospectively using acquired MR self-gating data, enabling cine imaging without the need for electrocardiogram (ECG) gating. Modification of the slice-select rephasing gradients of an ATR-SSFP sequence enables the acquisition of a 1D self-gating readout during the unused short repetition time (TR). Self-gating readouts are acquired during every TR of segmented, breath-held cardiac scans. A template-matching algorithm is designed to compute cardiac trigger points from the self-gating signals, and these trigger points are used for retrospective cine reconstruction. The proposed approach is compared with ECG-gated ATR-SSFP and balanced steady-state free precession (bSSFP) in ten volunteers and five patients. Results The difference of ECG and self-gating trigger times has a variability of 13 ± 11 ms (mean ± SD). Qualitative reviewer scoring and ranking indicate no statistically significant differences (P > 0.05) between self-gated and ECG-gated ATR-SSFP images. Quantitative blood-myocardial border sharpness is not significantly different among self-gated ATR-SSFP (0.61 ± 0.15 mm−1), ECG-gated ATR-SSFP (0.61 ± 0.15 mm−1), or conventional ECG-gated bSSFP cine MRI (0.59 ± 0.15 mm−1). Conclusion The proposed self-gated ATR-SSFP sequence enables fat-suppressed cardiac cine imaging at 1.5 T without the need for ECG gating and without decreasing the imaging efficiency of ATR-SSFP. PMID:24806049

  3. Learning robust pulses for generating universal quantum gates

    PubMed Central

    Dong, Daoyi; Wu, Chengzhi; Chen, Chunlin; Qi, Bo; Petersen, Ian R.; Nori, Franco

    2016-01-01

    Constructing a set of universal quantum gates is a fundamental task for quantum computation. The existence of noises, disturbances and fluctuations is unavoidable during the process of implementing quantum gates for most practical quantum systems. This paper employs a sampling-based learning method to find robust control pulses for generating a set of universal quantum gates. Numerical results show that the learned robust control fields are insensitive to disturbances, uncertainties and fluctuations during the process of realizing universal quantum gates. PMID:27782219

  4. Arbitrary nuclear-spin gates in diamond mediated by a nitrogen-vacancy-center electron spin

    NASA Astrophysics Data System (ADS)

    Casanova, J.; Wang, Z.-Y.; Plenio, M. B.

    2017-09-01

    We show that arbitrary N -qubit interactions among nuclear spins can be achieved efficiently in solid state quantum platforms, such as nitrogen vacancy centers in diamond, by exerting control only on the electron spin coupled to the nuclei. This allows to exploit nuclear spins as robust quantum registers and the direct measurement of nuclear many-body correlators. The method takes advantage of recently introduced dynamical decoupling techniques and avoids the necessity of external, slow, control on the nuclei. Our protocol is general, being applicable to other nuclear spin-based platforms with electronic spin defects acting as mediators as silicon carbide.

  5. Slime mould gates, roads and sensors

    NASA Astrophysics Data System (ADS)

    Adamatzky, Andrew

    2015-03-01

    The photographs present a wide range of problems solved by the slime mould P. polycephalum: imitation of human-made transport pathways, realisation of Boolean logical gates, fabrication of self-repairing routable biowires, implementation of delay elements in computing circuits, computational geometry, sensors and a would-be nervous system...

  6. Protected gates for topological quantum field theories

    NASA Astrophysics Data System (ADS)

    Koenig, Robert

    2015-03-01

    We give restrictions on the locality-preserving unitary automorphisms U, which are protected gates, for topologically ordered systems. For arbitrary anyon models, we show that such unitaries only generate a finite group, and hence do not provide universality. For abelian anyon models, we find that the logical action of U is contained in a proper subgroup of the generalized Clifford group. In the case D(?2), which describes Kitaev's toric code, this represents a tightening of statement previously obtained within the stabilizer framework (PRL 110:170503). For non-abelian models, we find that such automorphisms are very limited: for example, there is no non-trivial gate for Fibonacci anyons. For Ising anyons, protected gates are elements of the Pauli group. These results are derived by relating such automorphisms to symmetries of the underlying anyon model: protected gates realize automorphisms of the Verlinde algebra. We additionally use the compatibility with basis changes to characterize the logical action. This is joint work with M. Beverland, F. Pastawski, J. Preskill and S. Sijher.

  7. Corner Office Interview: Gates Foundation's Deborah Jacobs

    ERIC Educational Resources Information Center

    Miller, Rebecca

    2010-01-01

    U.S. libraries gave the world a top talent when Deborah Jacobs left her transformational role as City Librarian of Seattle in 2008 to head the Bill & Melinda Gates Foundation's Global Libraries program, the international sibling to the U.S. Libraries program. The initiative fosters national-scale projects with grantees in transitioning countries…

  8. Redesign of the GATE PET coincidence sorter

    NASA Astrophysics Data System (ADS)

    Strydhorst, Jared; Buvat, Irène

    2016-09-01

    The GATE software platform, based on the Geant4 toolkit for simulating particle interactions with matter, enables simulation of, among other medical imaging and treatment systems, positron emission tomography. However, at least one publication (Moraes et al 2015 Phys. Med. 31 43-8) has reported discrepancies between the expected results and those obtained using GATE simulations, specifically with respect to the coincidence sorter which processes single events detected by the scanner to find coincidence pairs. In particular, the current software appears to overestimate the number of ‘true’ coincidence pairs when in multi-window mode, while the delayed coincidence window, used to estimate the randoms present in the prompt coincidence window, underestimates the randoms. Both effects are particularly evident at high count rates. We have investigated this discrepancy and reproduced the reported problems. We have also rewritten the relevant portion of the GATE code to correct the issue. In this note we describe the modifications to the coincidence sorter and repeat the simulations which previously showed unexpected results. Some discrepancies remain in the estimation of the randoms with the single-window mode which are a consequence of the algorithm itself. In multi-window mode however, the simulation agrees exactly with the expected results. The modifications to the coincidence sorter code will be incorporated into the next release of GATE (> version 7.2).

  9. 104. DAM TAINTER GATE NONSUBMERGIBLE UPPER FRAME ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    104. DAM - TAINTER GATE - NON-SUBMERGIBLE - UPPER FRAME AND SKIN PLATE (ML-8-48/2-FS) June 1935 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  10. Corner Office Interview: Gates Foundation's Deborah Jacobs

    ERIC Educational Resources Information Center

    Miller, Rebecca

    2010-01-01

    U.S. libraries gave the world a top talent when Deborah Jacobs left her transformational role as City Librarian of Seattle in 2008 to head the Bill & Melinda Gates Foundation's Global Libraries program, the international sibling to the U.S. Libraries program. The initiative fosters national-scale projects with grantees in transitioning countries…

  11. Gates Fund Creates Plan for College Completion

    ERIC Educational Resources Information Center

    Gose, Ben

    2008-01-01

    The Bill & Melinda Gates Foundation plans to spend several hundred million dollars over the next five years to double the number of low-income young people who complete a college degree or certificate program by age 26. Foundation officials described the ambitious plan to an exclusive group of education leaders, citing 2025 as a target goal. If…

  12. A fail-safe CMOS logic gate

    NASA Technical Reports Server (NTRS)

    Bobin, V.; Whitaker, S.

    1990-01-01

    This paper reports a design technique to make Complex CMOS Gates fail-safe for a class of faults. Two classes of faults are defined. The fail-safe design presented has limited fault-tolerance capability. Multiple faults are also covered.

  13. Gates Fund Creates Plan for College Completion

    ERIC Educational Resources Information Center

    Gose, Ben

    2008-01-01

    The Bill & Melinda Gates Foundation plans to spend several hundred million dollars over the next five years to double the number of low-income young people who complete a college degree or certificate program by age 26. Foundation officials described the ambitious plan to an exclusive group of education leaders, citing 2025 as a target goal. If…

  14. Penumbras of Care beyond the Schoolhouse Gate.

    ERIC Educational Resources Information Center

    Hagenau, W. Paul

    1980-01-01

    Examines the responsibility of care owed to students by the school when the student is off the school premises. Concludes that prudent administrators must never presume that students automatically shed the protective mantle of the school's duty of care when they leave the schoolhouse gate. (Author/IRT)

  15. Pulse Shaping Entangling Gates and Error Supression

    NASA Astrophysics Data System (ADS)

    Hucul, D.; Hayes, D.; Clark, S. M.; Debnath, S.; Quraishi, Q.; Monroe, C.

    2011-05-01

    Control of spin dependent forces is important for generating entanglement and realizing quantum simulations in trapped ion systems. Here we propose and implement a composite pulse sequence based on the Molmer-Sorenson gate to decrease gate infidelity due to frequency and timing errors. The composite pulse sequence uses an optical frequency comb to drive Raman transitions simultaneously detuned from trapped ion transverse motional red and blue sideband frequencies. The spin dependent force displaces the ions in phase space, and the resulting spin-dependent geometric phase depends on the detuning. Voltage noise on the rf electrodes changes the detuning between the trapped ions' motional frequency and the laser, decreasing the fidelity of the gate. The composite pulse sequence consists of successive pulse trains from counter-propagating frequency combs with phase control of the microwave beatnote of the lasers to passively suppress detuning errors. We present the theory and experimental data with one and two ions where a gate is performed with a composite pulse sequence. This work supported by the U.S. ARO, IARPA, the DARPA OLE program, the MURI program; the NSF PIF Program; the NSF Physics Frontier Center at JQI; the European Commission AQUTE program; and the IC postdoc program administered by the NGA.

  16. Modelling and extraction procedure for gate insulator and fringing gate capacitance components of an MIS structure

    NASA Astrophysics Data System (ADS)

    Tinoco, J. C.; Martinez-Lopez, A. G.; Lezama, G.; Mendoza-Barrera, C.; Cerdeira, A.; Estrada, M.

    2016-07-01

    CMOS technology has been guided by the continuous reduction of MOS transistors used to fabricate integrated circuits. Additionally, the use of high-k dielectrics as well as a metal gate electrode have promoted the development of nanometric MOS transistors. Under this scenario, the proper modelling of the gate capacitance, with the aim of adequately evaluating the dielectric film thickness, becomes challenging for nanometric metal-insulator-semiconductor (MIS) structures due to the presence of extrinsic fringing capacitance components which affect the total gate capacitance. In this contribution, a complete intrinsic-extrinsic model for gate capacitance under accumulation of an MIS structure, together with an extraction procedure in order to independently determine the different capacitance components, is presented. ATLAS finite element simulation has been used to validate the proposed methodology.

  17. Capacitance modeling of gate material engineered cylindrical/surrounded gate MOSFETs for sensor applications

    NASA Astrophysics Data System (ADS)

    Verma, Jay Hind Kumar; Pratap, Yogesh; Haldar, Subhasis; Gupta, R. S.; Gupta, Mridula

    2015-12-01

    This paper presents charge based analytical drain current and capacitance model of material engineered Cylindrical/Surrounded Gate (CGT/SGT) MOSFET with nanogap cavity region for sensor applications. Material engineered i.e. dual material gate provides improvement in Short Channel Effects (SCEs) and cylindrical shape nanogap cavity region is used for sensing of biomolecule strength. The material engineered CGT/SGT MOSFET sensor electrically detect the targeted biomolecules of different strength by change in drain current and gate capacitance. Analysis has been carried out by using unified charge control based model derived from Poisson's equation. It is shown that sensitivity of changing biomolecules strength is more in gate capacitance than the drain current. The results so obtained are in good agreement with the 3D simulated data which validate the model.

  18. DISTANT VIEW OF EXTERIOR OD UPPER (NORTHERN) LOCK GATES, WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DISTANT VIEW OF EXTERIOR OD UPPER (NORTHERN) LOCK GATES, WITH TIMBER GUIDE WALL AND CONTROL HOUSE ON RIGHT AND TIMBER PYLONS AND LEVEE ON LEFT, BAFFLES ARE IN FRONT OF GATES FOR THE DRAINING OF THE LOCK, VIEW TOWARDS SOUTH - Moore Haven Lock, Hurricane Gate No. 1, Cross-State Canal, Okeechobee Intracoastal Waterway, Moore Haven, Glades County, FL

  19. Rapidly Reconfigurable All-Optical Universal Logic Gates

    SciTech Connect

    Goddard, L L; Kallman, J S; Bond, T C

    2006-06-21

    We present designs and simulations for a highly cascadable, rapidly reconfigurable, all-optical, universal logic gate. We will discuss the gate's expected performance, e.g. speed, fanout, and contrast ratio, as a function of the device layout and biasing conditions. The gate is a three terminal on-chip device that consists of: (1) the input optical port, (2) the gate selection port, and (3) the output optical port. The device can be built monolithically using a standard multiple quantum well graded index separate confinement heterostructure laser configuration. The gate can be rapidly and repeatedly reprogrammed to perform any of the basic digital logic operations by using an appropriate analog electrical or optical signal at the gate selection port. Specifically, the same gate can be selected to execute one of the 2 basic unary operations (NOT or COPY), or one of the 6 binary operations (OR, XOR, AND, NOR, XNOR, or NAND), or one of the many logic operations involving more than two inputs. The speed of the gate for logic operations as well as for reprogramming the function of the gate is primarily limited to the small signal modulation speed of a laser, which can be on the order of tens of GHz. The reprogrammable nature of the universal gate offers maximum flexibility and interchangeability for the end user since the entire application of a photonic integrated circuit built from cascaded universal logic gates can be changed simply by adjusting the gate selection port signals.

  20. SUPPRESSION OF AFTERPULSING IN PHOTOMULTIPLIERS BY GATING THE PHOTOCATHODE

    EPA Science Inventory

    A number of gating schemes to minimize the long-term afterpulse signal in photomultipliers have been evaluated. Blocking the excitation pulse by gating the photocathode was found to reduce the gate-on afterpulse background by a factor of 230 over that for nongated operation. Thi...

  1. SUPPRESSION OF AFTERPULSING IN PHOTOMULTIPLIERS BY GATING THE PHOTOCATHODE

    EPA Science Inventory

    A number of gating schemes to minimize the long-term afterpulse signal in photomultipliers have been evaluated. Blocking the excitation pulse by gating the photocathode was found to reduce the gate-on afterpulse background by a factor of 230 over that for nongated operation. Thi...

  2. 30 CFR 57.19100 - Shaft landing gates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft landing gates. 57.19100 Section 57.19100... Shafts § 57.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so... unloading shaft conveyances....

  3. 30 CFR 56.19100 - Shaft landing gates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft landing gates. 56.19100 Section 56.19100... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Personnel Hoisting Shafts § 56.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates...

  4. 2. CLOSEUP OF SOUTH FACADE OF UPPER FALLS GATE HOUSE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. CLOSEUP OF SOUTH FACADE OF UPPER FALLS GATE HOUSE, SHOWING TRASH RACKS, REMOVABLE STEEL DOORS, TRASH RAKE STRUCTURE, AND DERRICK, WINCH AND CABLE GATE LIFTING DEVICE, LOOKING SOUTH/SOUTHWEST. - Washington Water Power Spokane River Upper Falls Hydroelectric Development, Gate House, Spokane River, approximately 0.5 mile northeast of intersection of Spokane Falls Boulevard & Post Street, Spokane, Spokane County, WA

  5. 15. VIEW SHOWING WATER FLOWING THROUGH THE ORIGINAL DIVERSION GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW SHOWING WATER FLOWING THROUGH THE ORIGINAL DIVERSION GATE FROM THE OUTLET CHANNEL INTO THE BY-PASS CHANNEL LEADING TO THE ORIGINAL SOURIS RIVER CHANNEL (Note: this gate has since been replaced with concrete diversion gates, see HAER Photograph No ND-3-A-7) - Upper Souris National Wildlife Refuge, Dam 83, Souris River Basin, Foxholm, Surrey (England), ND

  6. Field calibration of submerged sluice gates in irrigation canals

    USDA-ARS?s Scientific Manuscript database

    Four rectangular sluice gates were calibrated for submerged-flow conditions using nearly 16,000 field-measured data points on Canal B of the B-XII irrigation scheme in Lebrija, Spain. Water depth and gate opening values were measured using acoustic sensors at each of the gate structures, and the dat...

  7. 30 CFR 56.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Closing cage doors or gates. 56.19070 Section 56.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 56.19070 Closing cage doors or gates. Cage doors or gates shall be closed...

  8. 30 CFR 57.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Closing cage doors or gates. 57.19070 Section 57.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 57.19070 Closing cage doors or gates. Cage doors or gates shall be closed...

  9. 30 CFR 56.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Closing cage doors or gates. 56.19070 Section 56.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 56.19070 Closing cage doors or gates. Cage doors or gates shall be closed...

  10. 30 CFR 57.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Closing cage doors or gates. 57.19070 Section 57.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 57.19070 Closing cage doors or gates. Cage doors or gates shall be closed...

  11. High-fidelity gates in quantum dot spin qubits

    PubMed Central

    Koh, Teck Seng; Coppersmith, S. N.; Friesen, Mark

    2013-01-01

    Several logical qubits and quantum gates have been proposed for semiconductor quantum dots controlled by voltages applied to top gates. The different schemes can be difficult to compare meaningfully. Here we develop a theoretical framework to evaluate disparate qubit-gating schemes on an equal footing. We apply the procedure to two types of double-dot qubits: the singlet–triplet and the semiconducting quantum dot hybrid qubit. We investigate three quantum gates that flip the qubit state: a DC pulsed gate, an AC gate based on logical qubit resonance, and a gate-like process known as stimulated Raman adiabatic passage. These gates are all mediated by an exchange interaction that is controlled experimentally using the interdot tunnel coupling g and the detuning ϵ, which sets the energy difference between the dots. Our procedure has two steps. First, we optimize the gate fidelity (f) for fixed g as a function of the other control parameters; this yields an that is universal for different types of gates. Next, we identify physical constraints on the control parameters; this yields an upper bound that is specific to the qubit-gate combination. We show that similar gate fidelities should be attainable for singlet-triplet qubits in isotopically purified Si, and for hybrid qubits in natural Si. Considerably lower fidelities are obtained for GaAs devices, due to the fluctuating magnetic fields ΔB produced by nuclear spins. PMID:24255105

  12. Hafnium dioxide gate dielectrics, metal gate electrodes, and phenomena occurring at their interfaces

    NASA Astrophysics Data System (ADS)

    Schaeffer, James Kenyon, III

    As metal-oxide-semiconductor field-effect transistor (MOSFET) gate lengths scale down below 45 nm, the gate oxide thickness approaches 1 nm equivalent oxide thickness. At this thickness, conventional silicon dioxide (SiO 2) gate dielectrics suffer from excessive gate leakage. Higher permittivity dielectrics are required to counter the increase in gate leakage. Hafnium dioxide (HfO2) has emerged as a promising dielectric candidate. HfO2 films deposited using metal organic chemical vapor deposition are being studied to determine the impact of process and annealing conditions on the physical and electrical properties of the gate dielectric. This study indicates that deposition and annealing temperatures influence the microstructure, density, impurity concentration, chemical environment of the impurities, and band-gap of the HfO2 dielectric. Correlations of the electrical and physical properties of the films indicate that impurities in the form of segregated carbon clusters, and low HfO2 density are detrimental to the leakage properties of the gate dielectric. Additionally, as the HfO2 thickness scales, the additional series capacitance due to poly-silicon depletion plays a larger roll in reducing the total gate capacitance. To solve this problem, high performance bulk MOSFETs will require dual metal gate electrodes possessing work functions near the silicon band edges for optimized drive current. This investigation evaluates TiN, Ta-Si-N, Ti-Al-N, WN, TaN, TaSi, Ir and IrO2 electrodes as candidate electrodes on HfO2 dielectrics. The metal-dielectric compatibility was studied by annealing the gate stacks at different temperatures. The physical stability and effective work functions of metal electrodes on HfO2 are discussed. Finally, Fermi level pinning of the metal is a barrier to identifying materials with appropriate threshold voltages. The contributions to the Fermi level pinning of platinum electrodes on HfO2 gate dielectrics are investigated by examining the

  13. The effect of pregabalin on sensorimotor gating in ‘low’ gating humans and mice

    PubMed Central

    Acheson, Dean T.; Stein, Murray B.; Paulus, Martin P.; Geyer, Mark A.; Risbrough, Victoria B.

    2013-01-01

    Pregabalin, an anticonvulsant and anxiolytic compound that binds to α2-δ auxiliary subunit Types 1 and 2 of voltage-gated calcium channels, has been shown to reduce excitatory neurotransmission partially through modulation of glutamatergic signaling. Prepulse inhibition (PPI) of startle is an operational measure of sensorimotor gating impacted by disruption of the glutamatergic system and is reduced in schizophrenia patients. Dysregulation of the glutamatergic system has also been implicated in the pathophysiology of schizophrenia. Here we tested the hypothesis that pregabalin may ameliorate PPI in a model of deficient gating in humans and mice. In study 1, 14 healthy human subjects participated in a within subjects, cross-over study with placebo, 50 mg or 200 mg pregabalin treatment prior to undergoing a PPI task. In study 2, 24 C57BL/6 mice underwent a similar procedure with vehicle, 30 and 100 mg/kg dose treatments. In both studies, subjects were assigned to a “Low” or “High” gating group using a median split procedure based on their PPI performance during placebo/vehicle. Drug effects were then examined across these groups. In humans, pregabalin treatment significantly increased PPI performance in the “low gating” group. In mice, pregabalin treatment significantly increased PPI in the low gating group but reduced PPI in the high gating group. Across species, pregabalin treatment improves PPI in subjects with low gating. These data support further exploration of pregabalin as a potential treatment for disorders characterized by sensorimotor gating deficits and glutamatergic hypersignaling, such as schizophrenia. PMID:22575075

  14. Gating current harmonics. III. Dynamic transients and steady states with intact sodium inactivation gating.

    PubMed Central

    Fohlmeister, J F; Adelman, W J

    1986-01-01

    Internally perfused squid giant axons with intact sodium inactivation gating were prepared for gating current experiments. Gating current records were obtained in sinusoidally driven dynamic steady states and as dynamic transients as functions of the mean membrane potential and the frequency of the command sinusoid. Controls were obtained after internal protease treatment of the axons that fully removed inactivation. The nonlinear analysis consisted of determining and interpreting the harmonic content in the current records. The results indicate the presence of three kinetic processes, two of which are associated with activation gating (the so-called primary and secondary processes), and the third with inactivation gating. The dynamic steady state data show that inactivation gating does not contribute a component to the gating current, and has no direct voltage-dependence of its own. Rather, the inactivation kinetics appear to be coupled to the primary activation kinetics, and the coupling mechanism appears to be one of reciprocal steric hindrance between two molecular components. The mechanism allows the channel to become inactivated without first entering the conducting state, and will do so in about 40 percent of depolarizing voltage-clamp steps to 0 mV. The derived model kinetics further indicate that the conducting state may flicker between open and closed with the lifetime of either state being 10 microseconds. Dynamic transients generated by the model kinetics (i.e., the behavior of the harmonic components as a function of time after an instantaneous change in the mean membrane potential from a holding potential of -80 mV) match the experimental dynamic transients in all details. These transients have a duration of 7-10 ms (depending on the level of depolarization), and are the result of the developing inactivation following the discontinuous voltage change. A detailed hypothetical molecular model of the channel and gating machinery is presented. PMID

  15. Allosteric gating mechanism underlies the flexible gating of KCNQ1 potassium channels.

    PubMed

    Osteen, Jeremiah D; Barro-Soria, Rene; Robey, Seth; Sampson, Kevin J; Kass, Robert S; Larsson, H Peter

    2012-05-01

    KCNQ1 (Kv7.1) is a unique member of the superfamily of voltage-gated K(+) channels in that it displays a remarkable range of gating behaviors tuned by coassembly with different β subunits of the KCNE family of proteins. To better understand the basis for the biophysical diversity of KCNQ1 channels, we here investigate the basis of KCNQ1 gating in the absence of β subunits using voltage-clamp fluorometry (VCF). In our previous study, we found the kinetics and voltage dependence of voltage-sensor movements are very similar to those of the channel gate, as if multiple voltage-sensor movements are not required to precede gate opening. Here, we have tested two different hypotheses to explain KCNQ1 gating: (i) KCNQ1 voltage sensors undergo a single concerted movement that leads to channel opening, or (ii) individual voltage-sensor movements lead to channel opening before all voltage sensors have moved. Here, we find that KCNQ1 voltage sensors move relatively independently, but that the channel can conduct before all voltage sensors have activated. We explore a KCNQ1 point mutation that causes some channels to transition to the open state even in the absence of voltage-sensor movement. To interpret these results, we adopt an allosteric gating scheme wherein KCNQ1 is able to transition to the open state after zero to four voltage-sensor movements. This model allows for widely varying gating behavior, depending on the relative strength of the opening transition, and suggests how KCNQ1 could be controlled by coassembly with different KCNE family members.

  16. Dosimetry applications in GATE Monte Carlo toolkit.

    PubMed

    Papadimitroulas, Panagiotis

    2017-02-21

    Monte Carlo (MC) simulations are a well-established method for studying physical processes in medical physics. The purpose of this review is to present GATE dosimetry applications on diagnostic and therapeutic simulated protocols. There is a significant need for accurate quantification of the absorbed dose in several specific applications such as preclinical and pediatric studies. GATE is an open-source MC toolkit for simulating imaging, radiotherapy (RT) and dosimetry applications in a user-friendly environment, which is well validated and widely accepted by the scientific community. In RT applications, during treatment planning, it is essential to accurately assess the deposited energy and the absorbed dose per tissue/organ of interest, as well as the local statistical uncertainty. Several types of realistic dosimetric applications are described including: molecular imaging, radio-immunotherapy, radiotherapy and brachytherapy. GATE has been efficiently used in several applications, such as Dose Point Kernels, S-values, Brachytherapy parameters, and has been compared against various MC codes which are considered as standard tools for decades. Furthermore, the presented studies show reliable modeling of particle beams when comparing experimental with simulated data. Examples of different dosimetric protocols are reported for individualized dosimetry and simulations combining imaging and therapy dose monitoring, with the use of modern computational phantoms. Personalization of medical protocols can be achieved by combining GATE MC simulations with anthropomorphic computational models and clinical anatomical data. This is a review study, covering several dosimetric applications of GATE, and the different tools used for modeling realistic clinical acquisitions with accurate dose assessment. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. Redox control of 20S proteasome gating.

    PubMed

    Silva, Gustavo M; Netto, Luis E S; Simões, Vanessa; Santos, Luiz F A; Gozzo, Fabio C; Demasi, Marcos A A; Oliveira, Cristiano L P; Bicev, Renata N; Klitzke, Clécio F; Sogayar, Mari C; Demasi, Marilene

    2012-06-01

    The proteasome is the primary contributor in intracellular proteolysis. Oxidized or unstructured proteins can be degraded via a ubiquitin- and ATP-independent process by the free 20S proteasome (20SPT). The mechanism by which these proteins enter the catalytic chamber is not understood thus far, although the 20SPT gating conformation is considered to be an important barrier to allowing proteins free entrance. We have previously shown that S-glutathiolation of the 20SPT is a post-translational modification affecting the proteasomal activities. The goal of this work was to investigate the mechanism that regulates 20SPT activity, which includes the identification of the Cys residues prone to S-glutathiolation. Modulation of 20SPT activity by proteasome gating is at least partially due to the S-glutathiolation of specific Cys residues. The gate was open when the 20SPT was S-glutathiolated, whereas following treatment with high concentrations of dithiothreitol, the gate was closed. S-glutathiolated 20SPT was more effective at degrading both oxidized and partially unfolded proteins than its reduced form. Only 2 out of 28 Cys were observed to be S-glutathiolated in the proteasomal α5 subunit of yeast cells grown to the stationary phase in glucose-containing medium. We demonstrate a redox post-translational regulatory mechanism controlling 20SPT activity. S-glutathiolation is a post-translational modification that triggers gate opening and thereby activates the proteolytic activities of free 20SPT. This process appears to be an important regulatory mechanism to intensify the removal of oxidized or unstructured proteins in stressful situations by a process independent of ubiquitination and ATP consumption. Antioxid. Redox Signal. 16, 1183-1194.

  18. Redox Control of 20S Proteasome Gating

    PubMed Central

    Silva, Gustavo M.; Simões, Vanessa; Santos, Luiz F.A.; Gozzo, Fabio C.; Demasi, Marcos A.A.; Oliveira, Cristiano L.P.; Bicev, Renata N.; Klitzke, Clécio F.; Sogayar, Mari C.

    2012-01-01

    Abstract The proteasome is the primary contributor in intracellular proteolysis. Oxidized or unstructured proteins can be degraded via a ubiquitin- and ATP-independent process by the free 20S proteasome (20SPT). The mechanism by which these proteins enter the catalytic chamber is not understood thus far, although the 20SPT gating conformation is considered to be an important barrier to allowing proteins free entrance. We have previously shown that S-glutathiolation of the 20SPT is a post-translational modification affecting the proteasomal activities. Aims: The goal of this work was to investigate the mechanism that regulates 20SPT activity, which includes the identification of the Cys residues prone to S-glutathiolation. Results: Modulation of 20SPT activity by proteasome gating is at least partially due to the S-glutathiolation of specific Cys residues. The gate was open when the 20SPT was S-glutathiolated, whereas following treatment with high concentrations of dithiothreitol, the gate was closed. S-glutathiolated 20SPT was more effective at degrading both oxidized and partially unfolded proteins than its reduced form. Only 2 out of 28 Cys were observed to be S-glutathiolated in the proteasomal α5 subunit of yeast cells grown to the stationary phase in glucose-containing medium. Innovation: We demonstrate a redox post-translational regulatory mechanism controlling 20SPT activity. Conclusion: S-glutathiolation is a post-translational modification that triggers gate opening and thereby activates the proteolytic activities of free 20SPT. This process appears to be an important regulatory mechanism to intensify the removal of oxidized or unstructured proteins in stressful situations by a process independent of ubiquitination and ATP consumption. Antioxid. Redox Signal. 16, 1183–1194. PMID:22229461

  19. Statistical Determination of the Gating Windows for Respiratory-Gated Radiotherapy Using a Visible Guiding System

    PubMed Central

    Oh, Se An; Yea, Ji Woon

    2016-01-01

    Respiratory-gated radiation therapy (RGRT) is used to minimize the radiation dose to normal tissue in lung-cancer patients. Although determining the gating window in the respiratory phase of patients is important in RGRT, it is not easy. Our aim was to determine the optimal gating window when using a visible guiding system for RGRT. Between April and October 2014, the breathing signals of 23 lung-cancer patients were recorded with a real-time position management (RPM) respiratory gating system (Varian, USA). We performed statistical analysis with breathing signals to find the optimal gating window for guided breathing in RGRT. When we compared breathing signals before and after the breathing training, 19 of the 23 patients showed statistically significant differences (p < 0.05). The standard deviation of the respiration signals after breathing training was lowest for phases of 30%–70%. The results showed that the optimal gating window in RGRT is 40% (30%–70%) with respect to repeatability for breathing after respiration training with the visible guiding system. RGRT was performed with the RPM system to confirm the usefulness of the visible guiding system. The RPM system and our visible guiding system improve the respiratory regularity, which in turn should improve the accuracy and efficiency of RGRT. PMID:27228097

  20. Statistical Determination of the Gating Windows for Respiratory-Gated Radiotherapy Using a Visible Guiding System.

    PubMed

    Oh, Se An; Yea, Ji Woon; Kim, Sung Kyu

    2016-01-01

    Respiratory-gated radiation therapy (RGRT) is used to minimize the radiation dose to normal tissue in lung-cancer patients. Although determining the gating window in the respiratory phase of patients is important in RGRT, it is not easy. Our aim was to determine the optimal gating window when using a visible guiding system for RGRT. Between April and October 2014, the breathing signals of 23 lung-cancer patients were recorded with a real-time position management (RPM) respiratory gating system (Varian, USA). We performed statistical analysis with breathing signals to find the optimal gating window for guided breathing in RGRT. When we compared breathing signals before and after the breathing training, 19 of the 23 patients showed statistically significant differences (p < 0.05). The standard deviation of the respiration signals after breathing training was lowest for phases of 30%-70%. The results showed that the optimal gating window in RGRT is 40% (30%-70%) with respect to repeatability for breathing after respiration training with the visible guiding system. RGRT was performed with the RPM system to confirm the usefulness of the visible guiding system. The RPM system and our visible guiding system improve the respiratory regularity, which in turn should improve the accuracy and efficiency of RGRT.

  1. Gating motions in voltage-gated potassium channels revealed by coarse-grained molecular dynamics simulations.

    PubMed

    Treptow, Werner; Marrink, Siewert-J; Tarek, Mounir

    2008-03-20

    Voltage-gated potassium (Kv) channels are ubiquitous transmembrane proteins involved in electric signaling of excitable tissues. A fundamental property of these channels is the ability to open or close in response to changes in the membrane potential. To date, their structure-based activation mechanism remains unclear, and there is a large controversy on how these gates function at the molecular level, in particular, how movements of the voltage sensor domain are coupled to channel gating. So far, all mechanisms proposed for this coupling are based on the crystal structure of the open voltage-gated Kv1.2 channel and structural models of the closed form based on electrophysiology experiments. Here, we use coarse-grain (CG) molecular dynamics simulations that allow conformational changes from the open to the closed form of the channel (embedded in its membrane environment) to be followed. Despite the low specificity of the CG force field, the obtained closed structure satisfies several experimental constraints. The overall results suggest a gating mechanism in which a lateral displacement the S4-S5 linker leads to a closing of the gate. Only a small up-down movement of the S4 helices is noticed. Additionally, the study suggests a peculiar upward motion of the intracellular tetramerization domain of the channel, hence providing a molecular view on how this domain may further regulate conduction in Kv channels.

  2. Accuracy and Consistency of Respiratory Gating in Abdominal Cancer Patients

    SciTech Connect

    Ge, Jiajia; Santanam, Lakshmi; Yang, Deshan; Parikh, Parag J.

    2013-03-01

    Purpose: To evaluate respiratory gating accuracy and intrafractional consistency for abdominal cancer patients treated with respiratory gated treatment on a regular linear accelerator system. Methods and Materials: Twelve abdominal patients implanted with fiducials were treated with amplitude-based respiratory-gated radiation therapy. On the basis of daily orthogonal fluoroscopy, the operator readjusted the couch position and gating window such that the fiducial was within a setup margin (fiducial-planning target volume [f-PTV]) when RPM indicated “beam-ON.” Fifty-five pre- and post-treatment fluoroscopic movie pairs with synchronized respiratory gating signal were recorded. Fiducial motion traces were extracted from the fluoroscopic movies using a template matching algorithm and correlated with f-PTV by registering the digitally reconstructed radiographs with the fluoroscopic movies. Treatment was determined to be “accurate” if 50% of the fiducial area stayed within f-PTV while beam-ON. For movie pairs that lost gating accuracy, a MATLAB program was used to assess whether the gating window was optimized, the external-internal correlation (EIC) changed, or the patient moved between movies. A series of safety margins from 0.5 mm to 3 mm was added to f-PTV for reassessing gating accuracy. Results: A decrease in gating accuracy was observed in 44% of movie pairs from daily fluoroscopic movies of 12 abdominal patients. Three main causes for inaccurate gating were identified as change of global EIC over time (∼43%), suboptimal gating setup (∼37%), and imperfect EIC within movie (∼13%). Conclusions: Inconsistent respiratory gating accuracy may occur within 1 treatment session even with a daily adjusted gating window. To improve or maintain gating accuracy during treatment, we suggest using at least a 2.5-mm safety margin to account for gating and setup uncertainties.

  3. G4-FETs as Universal and Programmable Logic Gates

    NASA Technical Reports Server (NTRS)

    Johnson, Travis; Fijany, Amir; Mojarradi, Mohammad; Vatan, Farrokh; Toomarian, Nikzad; Kolawa, Elizabeth; Cristoloveanu, Sorin; Blalock, Benjamin

    2007-01-01

    An analysis of a patented generic silicon- on-insulator (SOI) electronic device called a G4-FET has revealed that the device could be designed to function as a universal and programmable logic gate. The universality and programmability could be exploited to design logic circuits containing fewer discrete components than are required for conventional transistor-based circuits performing the same logic functions. A G4-FET is a combination of a junction field-effect transistor (JFET) and a metal oxide/semiconductor field-effect transistor (MOSFET) superimposed in a single silicon island and can therefore be regarded as two transistors sharing the same body. A G4-FET can also be regarded as a single transistor having four gates: two side junction-based gates, a top MOS gate, and a back gate activated by biasing of the SOI substrate. Each of these gates can be used to control the conduction characteristics of the transistor; this possibility creates new options for designing analog, radio-frequency, mixed-signal, and digital circuitry. With proper choice of the specific dimensions for the gates, channels, and ancillary features of the generic G4-FET, the device could be made to function as a three-input, one-output logic gate. As illustrated by the truth table in the top part of the figure, the behavior of this logic gate would be the inverse (the NOT) of that of a majority gate. In other words, the device would function as a NOT-majority gate. By simply adding an inverter, one could obtain a majority gate. In contrast, to construct a majority gate in conventional complementary metal oxide/semiconductor (CMOS) circuitry, one would need four three-input AND gates and a four-input OR gate, altogether containing 32 transistors.

  4. Experimental teleportation of a quantum controlled-NOT gate.

    PubMed

    Huang, Yun-Feng; Ren, Xi-Feng; Zhang, Yong-Sheng; Duan, Lu-Ming; Guo, Guang-Can

    2004-12-10

    Teleportation of quantum gates is a critical step for the implementation of quantum networking and teleportation-based models of quantum computation. We report an experimental demonstration of teleportation of the prototypical quantum controlled-NOT (CNOT) gate. Assisted with linear optical manipulations, photon entanglement produced from parametric down-conversion, and postselection from the coincidence measurements, we teleport the quantum CNOT gate from acting on local qubits to acting on remote qubits. The quality of the quantum gate teleportation is characterized through the method of quantum process tomography, with an average fidelity of 0.84 demonstrated for the teleported gate.

  5. Characterization of a Common-Gate Amplifier Using Ferroelectric Transistors

    NASA Technical Reports Server (NTRS)

    Hunt, Mitchell; Sayyah, Rana; MacLeod, Todd C.; Ho, Fat D.

    2011-01-01

    In this paper, the empirical data collected through experiments performed using a FeFET in the common-gate amplifier circuit is presented. The FeFET common-gate amplifier was characterized by varying all parameters in the circuit, such as load resistance, biasing of the transistor, and input voltages. Due to the polarization of the ferroelectric layer, the particular behavior of the FeFET common-gate amplifier presents interesting results. Furthermore, the differences between a FeFET common-gate amplifier and a MOSFET common-gate amplifier are examined.

  6. Gate-controlled ultraviolet photo-etching of graphene edges

    SciTech Connect

    Mitoma, Nobuhiko; Nouchi, Ryo

    2013-11-11

    The chemical reactivity of graphene under ultraviolet (UV) light irradiation is investigated under positive and negative gate electric fields. Graphene edges are selectively etched when negative gate voltages are applied while the reactivity is significantly suppressed for positive gate voltages. Oxygen adsorption onto graphene is significantly affected by the Fermi level of the final state achieved during previous electrical measurements. UV irradiation after negative-to-positive gate sweeps causes predominant oxygen desorption while UV irradiation after gate sweeps in the opposite direction causes etching of graphene edges.

  7. Edge-on gating effect in molecular wires.

    PubMed

    Lo, Wai-Yip; Bi, Wuguo; Li, Lianwei; Jung, In Hwan; Yu, Luping

    2015-02-11

    This work demonstrates edge-on chemical gating effect in molecular wires utilizing the pyridinoparacyclophane (PC) moiety as the gate. Different substituents with varied electronic demands are attached to the gate to simulate the effect of varying gating voltages similar to that in field-effect transistor (FET). It was observed that the orbital energy level and charge carrier's tunneling barriers can be tuned by changing the gating group from strong electron acceptors to strong electron donors. The single molecule conductance and current-voltage characteristics of this molecular system are truly similar to those expected for an actual single molecular transistor.

  8. 101. Photocopied August 1978. GENERAL VIEW OF COMPLETED COMPENSATING GATES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    101. Photocopied August 1978. GENERAL VIEW OF COMPLETED COMPENSATING GATES LOOKING NORTHWEST, AUGUST 5, 1916. THE COMPLETED 8 AMERICAN GATES ARE IN THE CENTER OF THE PHOTO: THE FIRST 4 CANADIAN GATES ARE IN THE BACKGROUND AT THE RIGHT. GATES 5-8 HAVE NOT BEEN BUILT, NEITHER HAS THE DIKE CONNECTING GATE 16 (FAR LEFT) WITH THE DIKE OF THE GOVERNMENT HYDROELECTRIC PLANT HEAD RACE. THE BREAKWATER IN FRONT OF THE WORKS HAS NOT YET BEEN DREDGED OUT. (708) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  9. Free-exciton states in crystalline GaTe

    NASA Astrophysics Data System (ADS)

    Wan, J. Z.; Brebner, J. L.; Leonelli, R.

    1995-12-01

    Polarized properties of both the singlet and triplet ground exciton states in the photoluminescence and transmission spectra of crystalline GaTe are explained based on the possible symmetry properties of the energy band edge of GaTe. Some experimental results about excited exciton states in GaTe are presented and discussed. The energy positions of exciton series in GaTe follow the three-dimensional direct allowed Wannier exciton formula just as in the the other III-VI layered compounds of GaSe and InSe. The nonthermalized, ``hot'' nature of excitons inside GaTe under higher optical excitation intensities is also discussed.

  10. Retention and switching kinetics of protonated gate field effect transistors

    SciTech Connect

    DEVINE,R.A.B.; HERRERA,GILBERT V.

    2000-05-23

    The switching and memory retention time has been measured in 50 {micro}m gatelength pseudo-non-volatile memory MOSFETS containing, protonated 40 nm gate oxides. Times of the order of 3.3 seconds are observed for fields of 3 MV cm{sup {minus}1}. The retention time with protons placed either at the gate oxide/substrate or gate oxide/gate electrode interfaces is found to better than 96{percent} after 5,000 seconds. Measurement of the time dependence of the source-drain current during switching provides clear evidence for the presence of dispersive proton transport through the gate oxide.

  11. Retention and Switching Kinetics of Protonated Gate Field Effect Transistors

    SciTech Connect

    DEVINE,R.A.B.; HERRERA,GILBERT V.

    2000-06-27

    The switching and memory retention time has been measured in 50 {micro}m gatelength pseudo-non-volatile memory MOSFETs containing, protonated 40 nm gate oxides. Times of the order of 3.3 seconds are observed for fields of 3 MV cm{sup {minus}1}. The retention time with protons placed either at the gate oxide/substrate or gate oxide/gate electrode interfaces is found to better than 96% after 5,000 seconds. Measurement of the time dependence of the source-drain current during switching provides clear evidence for the presence of dispersive proton transport through the gate oxide.

  12. Gating of Permanent Molds for Aluminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-01-01

    This report summarizes a two-year project, DE-FC07-011D13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was to determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings. Equipment and procedure for real time X-Ray radiography of molten aluminum flow into permanent molds have been developed. Other studies have been conducted using water flow and behavior of liquid aluminum in sand mold using real time photography. This investigation utilizes graphite molds transparent to X-Rays making it possible to observe the flow pattern through a number of vertically oriented grating systems. These have included systems that are choked at the base of a rounded vertical sprue and vertical gating systems with a variety of different ingates into the bottom of a mold cavity. These systems have also been changed to include gating systems with vertical and horizontal gate configurations. Several conclusions can be derived from this study. A sprue-well, as designed in these experiments, does not eliminate the vena contracta. Because of the swirling at the sprue-base, the circulating metal begins to push the entering metal stream toward the open runner mitigating the intended effect of the sprue-well. Improved designs of

  13. Optimized pulse shapes for a resonator-induced phase gate

    NASA Astrophysics Data System (ADS)

    Cross, Andrew W.; Gambetta, Jay M.

    2015-03-01

    The resonator-induced phase gate is a multiqubit controlled-phase gate for fixed-frequency superconducting qubits. Through off-resonant driving of a bus resonator, statically coupled qubits acquire a state-dependent phase. However, photon loss leads to dephasing during the gate, and any residual entanglement between the resonator and qubits after the gate leads to decoherence. Here we consider how to shape the drive pulse to minimize these unwanted effects. First, we review how the gate's entangling and dephasing rates depend on the system parameters and validate closed-form solutions against direct numerical solution of a master equation. Next, we propose spline pulse shapes that reduce residual qubit-bus entanglement, are robust to imprecise knowledge of the resonator shift, and can be shortened by using higher-degree polynomials. Finally, we present a procedure that optimizes over the subspace of pulses that leave the resonator unpopulated. This finds shaped drive pulses that further reduce the gate duration. Assuming realistic parameters, we exhibit shaped pulses that have the potential to realize ˜212 ns spline pulse gates and ˜120 ns optimized gates with ˜6 ×10-4 average gate infidelity. These examples do not represent fundamental limits of the gate and, in principle, even shorter gates may be achievable.

  14. Connectable DNA logic gates: OR and XOR logics.

    PubMed

    Gerasimova, Yulia V; Kolpashchikov, Dmitry M

    2012-03-05

    Modern computer processors are based on semiconductor logic gates connected to each other in complex circuits. This study contributes to the development of a new class of connectable logic gates made of DNA in which the transfer of oligonucleotide fragments as input/output signals occurs upon hybridization of DNA sequences. The DNA strands responsible for a logic function form associates containing immobile DNA four-way junction structures when the signal is high and dissociate into separate strands when the signal is low. A basic set of logic gates (NOT, AND, and OR) was designed. Two NOT gates, two AND gates, and an OR gate were connected in a network that corresponds to an XOR logic function. The design of the logic gates presented here may contribute to the development of the first biocompatible molecular computer. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Local Ambipolar Graphene Field Effect Transistors via Metal Side Gates

    NASA Astrophysics Data System (ADS)

    Tian, Jifa; Jauregui, Luis; Lopez, Gabriel; Cao, Helin; Chen, Yong

    2010-03-01

    We fabricated local graphene field effect transistors (FET) based on metal side gates. The characteristic ambipolar field effect of graphene device was observed by sweeping only the voltage of a local metal side gate. The local charge neutrality point of the side-gate graphene FET can be tuned in a large voltage range from positive to negative by a second side gate. Furthermore, we observed that the field effect due to the side gate can be appreciably weakened by electrically grounding the back gate compared to floating the back gate. The experimental results can be well explained by electrostatic simulation using COMSOL. Our technique offers a simple method for local tuning of charge density of graphene nanodevices while avoiding coating graphene surface with dielectrics, which may cause contamination and degradation of graphene.

  16. Quasi-specific access of the potassium channel inactivation gate.

    PubMed

    Venkataraman, Gaurav; Srikumar, Deepa; Holmgren, Miguel

    2014-06-09

    Many voltage-gated potassium channels open in response to membrane depolarization and then inactivate within milliseconds. Neurons use these channels to tune their excitability. In Shaker K(+) channels, inactivation is caused by the cytoplasmic amino terminus, termed the inactivation gate. Despite having four such gates, inactivation is caused by the movement of a single gate into a position that occludes ion permeation. The pathway that this single inactivation gate takes into its inactivating position remains unknown. Here we show that a single gate threads through the intracellular entryway of its own subunit, but the tip of the gate has sufficient freedom to interact with all four subunits deep in the pore, and does so with equal probability. This pathway demonstrates that flexibility afforded by the inactivation peptide segment at the tip of the N-terminus is used to mediate function.

  17. Nonadiabatic holonomic gates realized by a single-shot implementation

    NASA Astrophysics Data System (ADS)

    Xu, G. F.; Liu, C. L.; Zhao, P. Z.; Tong, D. M.

    2015-11-01

    Nonadiabatic holonomic quantum computation has received increasing attention due to its robustness against control errors. However, all the previous schemes have to use at least two sequentially implemented gates to realize a general one-qubit gate. In this paper we put forward a scheme by which one can directly realize an arbitrary holonomic one-qubit gate with a single-shot implementation, avoiding the extra work of combining two gates into one. Based on a three-level model driven by laser pulses, we show that any single-qubit holonomic gate can be realized by varying the detuning, amplitude, and phase of lasers. Our scheme is compatible with previously proposed nonadiabatic holonomic two-qubit gates, combining with which the arbitrary holonomic one-qubit gates can play universal nonadiabatic holonomic quantum computation. We also investigate the effects of some unavoidable realistic errors on our scheme.

  18. Site-Directed Spin Labeling Reveals Pentameric Ligand-Gated Ion Channel Gating Motions

    PubMed Central

    Dellisanti, Cosma D.; Ghosh, Borna; Hanson, Susan M.; Raspanti, James M.; Grant, Valerie A.; Diarra, Gaoussou M.; Schuh, Abby M.; Satyshur, Kenneth; Klug, Candice S.; Czajkowski, Cynthia

    2013-01-01

    Pentameric ligand-gated ion channels (pLGICs) are neurotransmitter-activated receptors that mediate fast synaptic transmission. In pLGICs, binding of agonist to the extracellular domain triggers a structural rearrangement that leads to the opening of an ion-conducting pore in the transmembrane domain and, in the continued presence of neurotransmitter, the channels desensitize (close). The flexible loops in each subunit that connect the extracellular binding domain (loops 2, 7, and 9) to the transmembrane channel domain (M2–M3 loop) are essential for coupling ligand binding to channel gating. Comparing the crystal structures of two bacterial pLGIC homologues, ELIC and the proton-activated GLIC, suggests channel gating is associated with rearrangements in these loops, but whether these motions accurately predict the motions in functional lipid-embedded pLGICs is unknown. Here, using site-directed spin labeling (SDSL) electron paramagnetic resonance (EPR) spectroscopy and functional GLIC channels reconstituted into liposomes, we examined if, and how far, the loops at the ECD/TMD gating interface move during proton-dependent gating transitions from the resting to desensitized state. Loop 9 moves ∼9 Å inward toward the channel lumen in response to proton-induced desensitization. Loop 9 motions were not observed when GLIC was in detergent micelles, suggesting detergent solubilization traps the protein in a nonactivatable state and lipids are required for functional gating transitions. Proton-induced desensitization immobilizes loop 2 with little change in position. Proton-induced motion of the M2–M3 loop was not observed, suggesting its conformation is nearly identical in closed and desensitized states. Our experimentally derived distance measurements of spin-labeled GLIC suggest ELIC is not a good model for the functional resting state of GLIC, and that the crystal structure of GLIC does not correspond to a desensitized state. These findings advance our

  19. Gate Set Tomography on two qubits

    NASA Astrophysics Data System (ADS)

    Nielsen, Erik; Blume-Kohout, Robin; Gamble, John; Rudinger, Kenneth

    Gate set tomography (GST) is a method for characterizing quantum gates that does not require pre-calibrated operations, and has been used to both certify and improve the operation of single qubits. We analyze the performance of GST applied to a simulated two-qubit system, and show that Heisenberg scaling is achieved in this case. We present a GST analysis of preliminary two-qubit experimental data, and draw comparisons with the simulated data case. Finally, we will discuss recent theoretical developments that have improved the efficiency of GST estimation procedures, and which are particularly beneficial when characterizing two qubit systems. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  20. SWNT array resonant gate MOS transistor.

    PubMed

    Arun, A; Campidelli, S; Filoramo, A; Derycke, V; Salet, P; Ionescu, A M; Goffman, M F

    2011-02-04

    We show that thin horizontal arrays of single wall carbon nanotubes (SWNTs) suspended above the channel of silicon MOSFETs can be used as vibrating gate electrodes. This new class of nano-electromechanical system (NEMS) combines the unique mechanical and electronic properties of SWNTs with an integrated silicon-based motion detection. Its electrical response exhibits a clear signature of the mechanical resonance of SWNT arrays (120-150 MHz) showing that these thin horizontal arrays behave as a cohesive, rigid and elastic body membrane with a Young's modulus in the order of 1-10 GPa and ultra-low mass. The resonant frequency can be tuned by the gate voltage and its dependence is well understood within the continuum mechanics framework.

  1. Method for voltage-gated protein fractionation

    DOEpatents

    Hatch, Anson [Tracy, CA; Singh, Anup K [Danville, CA

    2012-04-24

    We report unique findings on the voltage dependence of protein exclusion from the pores of nanoporous polymer exclusion membranes. The pores are small enough that proteins are excluded from passage with low applied electric fields, but increasing the field enables proteins to pass through. The requisite field necessary for a change in exclusion is protein-specific with a correlation to protein size. The field-dependence of exclusion is important to consider for preconcentration applications. The ability to selectively gate proteins at exclusion membranes is also a promising means for manipulating and characterizing proteins. We show that field-gated exclusion can be used to selectively remove proteins from a mixture, or to selectively trap protein at one exclusion membrane in a series.

  2. Water-gel for gating graphene transistors.

    PubMed

    Kim, Beom Joon; Um, Soong Ho; Song, Woo Chul; Kim, Yong Ho; Kang, Moon Sung; Cho, Jeong Ho

    2014-05-14

    Water, the primary electrolyte in biology, attracts significant interest as an electrolyte-type dielectric material for transistors compatible with biological systems. Unfortunately, the fluidic nature and low ionic conductivity of water prevents its practical usage in such applications. Here, we describe the development of a solid state, megahertz-operating, water-based gate dielectric system for operating graphene transistors. The new electrolyte systems were prepared by dissolving metal-substituted DNA polyelectrolytes into water. The addition of these biocompatible polyelectrolytes induced hydrogelation to provide solid-state integrity to the system. They also enhanced the ionic conductivities of the electrolytes, which in turn led to the quick formation of an electric double layer at the graphene/electrolyte interface that is beneficial for modulating currents in graphene transistors at high frequencies. At the optimized conditions, the Na-DNA water-gel-gated flexible transistors and inverters were operated at frequencies above 1 MHz and 100 kHz, respectively.

  3. Ultrasonic evaluation of flood gate tendons

    SciTech Connect

    Thomas, G.; Brown, A.

    1997-10-01

    Our water resources infrastructure is susceptible to aging degradation just like the rest of this country`s infrastructure. A critical component of the water supply system is the flood gate that controls the outflow from dams.Long steel rods called tendons attach these radial gates to the concrete in the dam. The tendons are typically forty feet long and over one inch in diameter. Moisture may seep into the grout around the tendons and cause corrosion. Lawrence Livermore National Laboratory is working with the California Department of Water Resources to develop advanced ultrasonic techniques for nondestructively inspecting their tendons. A unique transducer was designed and fabricated to interrogate the entire tendon. A robust,portable unit was assembled that included a computer controlled data acquisition system and specialized data processing software to analyze the ultrasonic signals. This system was tested on laboratory specimens and is presently being fielded at two dam sites.

  4. Multifunctional Logic Gate Controlled by Supply Voltage

    NASA Technical Reports Server (NTRS)

    Stoica, Adrian; Zebulum, Ricardo

    2005-01-01

    A complementary metal oxide/semiconductor (CMOS) electronic circuit functions as a NAND gate at a power-supply potential (V(sub dd)) of 3.3 V and as NOR gate for V(sub dd) = 1.8 V. In the intermediate V(sub dd) range of 1.8 to 3.3 V, this circuit performs a function intermediate between NAND and NOR with degraded noise margin. Like the circuit of the immediately preceding article, this circuit serves as a demonstration of the evolutionary approach to design of polymorphic electronics -- a technological discipline that emphasizes evolution of the design of a circuit to perform different analog and/or digital functions under different conditions. In this instance, the different conditions are different values of V(sub dd).

  5. Multifunctional Logic Gate Controlled by Temperature

    NASA Technical Reports Server (NTRS)

    Stoica, Adrian; Zebulum, Ricardo

    2005-01-01

    A complementary metal oxide/semiconductor (CMOS) electronic circuit has been designed to function as a NAND gate at a temperature between 0 and 80 deg C and as a NOR gate at temperatures from 120 to 200 C. In the intermediate temperature range of 80 to 120 C, this circuit is expected to perform a function intermediate between NAND and NOR with degraded noise margin. The process of designing the circuit and the planned fabrication and testing of the circuit are parts of demonstration of polymorphic electronics a technological discipline that emphasizes designing the same circuit to perform different analog and/or digital functions under different conditions. In this case, the different conditions are different temperatures.

  6. Submicrometer polysilicon gate CMOS/SOS technology

    NASA Astrophysics Data System (ADS)

    Ipri, A. C.; Sokoloski, J. C.; Flatley, D. W.

    1980-07-01

    A process is described for the fabrication of CMOS/SOS submicrometer devices and integrated circuits. The process utilizes the lateral diffusion of boron into polycrystalline silicon and a subsequent anisotropic etchant to define the narrow poly gates. Devices with channel lengths as small as 0.3 micron have been fabricated and characterized. Both avalanche and tunnel injection of carriers into the gate dielectric have been measured and both can have an impact on the limit of voltage operation. At present, these mechanisms appear to place an upper limit of about 8 V on the operating voltage of dynamic circuits containing 0.5-micron channel length devices. The propagation delay of 0.5-micron channel length CMOS/SOS inverters is about 200 ps at 5 V and dynamic binary counters will operate with a maximum input frequency of 550 MHz and 8 V while dissipating 130 mW.

  7. Structure of molten Ga-Te eutectic

    SciTech Connect

    Dutchak, Ya.I.; Mudryi, S.I.; Kozyrenko, V.N.

    1988-02-01

    We have made an x-ray study of the Ga-Te eutectic liquid. The phase diagram shows a series of compounds as well as immiscibility regions for two liquid phases and the eutectic. The compounds GaTe and Ga/sub 2/Te/sub 3/ melt congruently. The phase diagram is complicated, and the phase state varies substantially with the component ratio. The liquid eutectic (87 at. % Te) was examined with a high-temperature diffractometer intended particularly for liquids; Cu K..cap alpha.. radiation was used, which was monochromatized with LiF. An integral Fourier transformation was used to calculate the radial distributions for the atoms and the density; the first were used to derive the most likely shortest interatomic distances, while the second gave the mean coordination numbers.

  8. Philosophy of voltage-gated proton channels

    PubMed Central

    DeCoursey, Thomas E.; Hosler, Jonathan

    2014-01-01

    In this review, voltage-gated proton channels are considered from a mainly teleological perspective. Why do proton channels exist? What good are they? Why did they go to such lengths to develop several unique hallmark properties such as extreme selectivity and ΔpH-dependent gating? Why is their current so minuscule? How do they manage to be so selective? What is the basis for our belief that they conduct H+ and not OH–? Why do they exist in many species as dimers when the monomeric form seems to work quite well? It is hoped that pondering these questions will provide an introduction to these channels and a way to logically organize their peculiar properties as well as to understand how they are able to carry out some of their better-established biological functions. PMID:24352668

  9. Surface conduction in encapsulated topological gated structures

    NASA Astrophysics Data System (ADS)

    Deshko, Yury; Korzhovska, Inna; Zhao, Lukas; Arefe, Ghidewon; Konczykowski, Marcin; Krusin-Elbaum, Lia

    2015-03-01

    In three-dimensional (3D) topological insulators (TIs), the surface Dirac fermions intermix with the conducting bulk, thereby complicating access to the low-energy surface charge transport or magnetic response. The subsurface 2D states of bulk origin are vulnerable to bandbending due to surface adatoms, a band modification thought to be responsible for the `ageing' effect. To minimize this effect, we have developed an inert environment mechanical exfoliation technique to fabricate transistor-like gated structures in which prototypical binary TIs as well as ultra-low bulk carrier density ternaries (such as Bi2Te2Se) were encapsulated by thin h-BN layers, with electrical contacts made using exfoliated graphene. The effects of electrostatic tuning by the gate bias voltage on surface conductivity as a function of thickness of the TI layers and the variation with disorder will be presented. Supported by NSF-DMR-1312483, and DOD-W911NF-13-1-0159.

  10. DIFMOS - A floating-gate electrically erasable nonvolatile semiconductor memory technology. [Dual Injector Floating-gate MOS

    NASA Technical Reports Server (NTRS)

    Gosney, W. M.

    1977-01-01

    Electrically alterable read-only memories (EAROM's) or reprogrammable read-only memories (RPROM's) can be fabricated using a single-level metal-gate p-channel MOS technology with all conventional processing steps. Given the acronym DIFMOS for dual-injector floating-gate MOS, this technology utilizes the floating-gate technique for nonvolatile storage of data. Avalanche injection of hot electrons through gate oxide from a special injector diode in each bit is used to charge the floating gates. A second injector structure included in each bit permits discharge of the floating gate by avalanche injection of holes through gate oxide. The overall design of the DIFMOS bit is dictated by the physical considerations required for each of the avalanche injector types. The end result is a circuit technology which can provide fully decoded bit-erasable EAROM-type circuits using conventional manufacturing techniques.

  11. Advantages of gated silicon single photon detectors

    NASA Astrophysics Data System (ADS)

    Legré, Matthieu; Lunghi, Tommaso; Stucki, Damien; Zbinden, Hugo

    2013-05-01

    We present gated silicon single photon detectors based on two commercially available avalanche photodiodes (APDs) and one customised APD from ID Quantique SA. This customised APD is used in a commercially available device called id110. A brief comparison of the two commercial APDs is presented. Then, the charge persistence effect of all of those detectors that occurs just after a strong illumination is shown and discussed.

  12. Cluster computing software for GATE simulations.

    PubMed

    De Beenhouwer, Jan; Staelens, Steven; Kruecker, Dirk; Ferrer, Ludovic; D'Asseler, Yves; Lemahieu, Ignace; Rannou, Fernando R

    2007-06-01

    Geometry and tracking (GEANT4) is a Monte Carlo package designed for high energy physics experiments. It is used as the basis layer for Monte Carlo simulations of nuclear medicine acquisition systems in GEANT4 Application for Tomographic Emission (GATE). GATE allows the user to realistically model experiments using accurate physics models and time synchronization for detector movement through a script language contained in a macro file. The downside of this high accuracy is long computation time. This paper describes a platform independent computing approach for running GATE simulations on a cluster of computers in order to reduce the overall simulation time. Our software automatically creates fully resolved, nonparametrized macros accompanied with an on-the-fly generated cluster specific submit file used to launch the simulations. The scalability of GATE simulations on a cluster is investigated for two imaging modalities, positron emission tomography (PET) and single photon emission computed tomography (SPECT). Due to a higher sensitivity, PET simulations are characterized by relatively high data output rates that create rather large output files. SPECT simulations, on the other hand, have lower data output rates but require a long collimator setup time. Both of these characteristics hamper scalability as a function of the number of CPUs. The scalability of PET simulations is improved here by the development of a fast output merger. The scalability of SPECT simulations is improved by greatly reducing the collimator setup time. Accordingly, these two new developments result in higher scalability for both PET and SPECT simulations and reduce the computation time to more practical values.

  13. Bimetal switches in an AND logic gate

    NASA Astrophysics Data System (ADS)

    Lubrica, Joel V.; Lubrica, Quantum Yuri B.

    2016-09-01

    In this frontline, we use bimetal switches to provide inputs in an electrical AND logic gate. These switches can be obtained from the pre-heat starters of fluorescent lamps, by safely removing the glass enclosure. They may be activated by small open flames. This frontline has a historical aspect because fluorescent lamps, together with pre-heat starters, are now being replaced by compact fluorescent, halogen, and LED lamps.

  14. Cluster computing software for GATE simulations

    SciTech Connect

    Beenhouwer, Jan de; Staelens, Steven; Kruecker, Dirk; Ferrer, Ludovic; D'Asseler, Yves; Lemahieu, Ignace; Rannou, Fernando R.

    2007-06-15

    Geometry and tracking (GEANT4) is a Monte Carlo package designed for high energy physics experiments. It is used as the basis layer for Monte Carlo simulations of nuclear medicine acquisition systems in GEANT4 Application for Tomographic Emission (GATE). GATE allows the user to realistically model experiments using accurate physics models and time synchronization for detector movement through a script language contained in a macro file. The downside of this high accuracy is long computation time. This paper describes a platform independent computing approach for running GATE simulations on a cluster of computers in order to reduce the overall simulation time. Our software automatically creates fully resolved, nonparametrized macros accompanied with an on-the-fly generated cluster specific submit file used to launch the simulations. The scalability of GATE simulations on a cluster is investigated for two imaging modalities, positron emission tomography (PET) and single photon emission computed tomography (SPECT). Due to a higher sensitivity, PET simulations are characterized by relatively high data output rates that create rather large output files. SPECT simulations, on the other hand, have lower data output rates but require a long collimator setup time. Both of these characteristics hamper scalability as a function of the number of CPUs. The scalability of PET simulations is improved here by the development of a fast output merger. The scalability of SPECT simulations is improved by greatly reducing the collimator setup time. Accordingly, these two new developments result in higher scalability for both PET and SPECT simulations and reduce the computation time to more practical values.

  15. Cortical Gating of Oropharyngeal Sensory Stimuli

    PubMed Central

    Wheeler-Hegland, Karen; Pitts, Teresa; Davenport, Paul W.

    2010-01-01

    Somatosensory evoked potentials provide a measure of cortical neuronal activation in response to various types of sensory stimuli. In order to prevent flooding of the cortex with redundant information various sensory stimuli are gated cortically such that response to stimulus 2 (S2) is significantly reduced in amplitude compared to stimulus 1 (S1). Upper airway protective mechanisms, such as swallowing and cough, are dependent on sensory input for triggering and modifying their motor output. Thus, it was hypothesized that central neural gating would be absent for paired-air puff stimuli applied to the oropharynx. Twenty-three healthy adults (18–35 years) served as research participants. Pharyngeal sensory evoked potentials (PSEPs) were measured via 32-electrode cap (10–20 system) connected to SynAmps2 Neuroscan EEG System. Paired-pulse air puffs were delivered with an inter-stimulus interval of 500 ms to the oropharynx using a thin polyethylene tube connected to a flexible laryngoscope. Data were analyzed using descriptive statistics and a repeated measures analysis of variance. There were no significant differences found for the amplitudes S1 and S2 for any of the four component PSEP peaks. Mean gating ratios were above 0.90 for each peak. Results supports our hypothesis that sensory central neural gating would be absent for component PSEP peaks with paired-pulse stimuli delivered to the oropharynx. This may be related to the need for constant sensory monitoring necessary for adequate airway protection associated with swallowing and coughing. PMID:21423402

  16. Voltage Gated Ion Channel Function: Gating, Conduction, and the Role of Water and Protons

    PubMed Central

    Kariev, Alisher M.; Green, Michael E.

    2012-01-01

    Ion channels, which are found in every biological cell, regulate the concentration of electrolytes, and are responsible for multiple biological functions, including in particular the propagation of nerve impulses. The channels with the latter function are gated (opened) by a voltage signal, which allows Na+ into the cell and K+ out. These channels have several positively charged amino acids on a transmembrane domain of their voltage sensor, and it is generally considered, based primarily on two lines of experimental evidence, that these charges move with respect to the membrane to open the channel. At least three forms of motion, with greatly differing extents and mechanisms of motion, have been proposed. There is a “gating current”, a capacitative current preceding the channel opening, that corresponds to several charges (for one class of channel typically 12–13) crossing the membrane field, which may not require protein physically crossing a large fraction of the membrane. The coupling to the opening of the channel would in these models depend on the motion. The conduction itself is usually assumed to require the “gate” of the channel to be pulled apart to allow ions to enter as a section of the protein partially crosses the membrane, and a selectivity filter at the opposite end of the channel determines the ion which is allowed to pass through. We will here primarily consider K+ channels, although Na+ channels are similar. We propose that the mechanism of gating differs from that which is generally accepted, in that the positively charged residues need not move (there may be some motion, but not as gating current). Instead, protons may constitute the gating current, causing the gate to open; opening consists of only increasing the diameter at the gate from approximately 6 Å to approximately 12 Å. We propose in addition that the gate oscillates rather than simply opens, and the ion experiences a barrier to its motion across the channel that is tuned

  17. Optical parametrically gated microscopy in scattering media.

    PubMed

    Zhao, Youbo; Adie, Steven G; Tu, Haohua; Liu, Yuan; Graf, Benedikt W; Chaney, Eric J; Marjanovic, Marina; Boppart, Stephen A

    2014-09-22

    High-resolution imaging in turbid media has been limited by the intrinsic compromise between the gating efficiency (removal of multiply-scattered light background) and signal strength in the existing optical gating techniques. This leads to shallow depths due to the weak ballistic signal, and/or degraded resolution due to the strong multiply-scattering background--the well-known trade-off between resolution and imaging depth in scattering samples. In this work, we employ a nonlinear optics based optical parametric amplifier (OPA) to address this challenge. We demonstrate that both the imaging depth and the spatial resolution in turbid media can be enhanced simultaneously by the OPA, which provides a high level of signal gain as well as an inherent nonlinear optical gate. This technology shifts the nonlinear interaction to an optical crystal placed in the detection arm (image plane), rather than in the sample, which can be used to exploit the benefits given by the high-order parametric process and the use of an intense laser field. The coherent process makes the OPA potentially useful as a general-purpose optical amplifier applicable to a wide range of optical imaging techniques.

  18. A CNOT gate in a glass chip

    NASA Astrophysics Data System (ADS)

    Alsing, Paul M.; Kreymerman, Grigoriy; Miller, Warner A.

    2015-05-01

    In our earlier work we posited that simple quantum gates and quantum algorithms can be designed utilizing the diffraction phenomena of a photon within a multiplexed holographic element. The quantum eigenstates we use are the photons transverse linear momentum (LM) as measured by the number of waves of tilt across the aperture. Two properties of linear optical quantum computing (LOQC) within the circuit model make this approach attractive. First, any conditional measurement can be commuted in time with any unitary quantum gate; and second, photon entanglement can be encoded as a superposition state of a single photon in a higher-dimensional state space afforded by LM. We describe here our experimental results for construction a controlled NOT (CNOT) gate logic within a holographic medium, and present the quantum state tomography for this device. Our theoretical and numerical results indicate that OptiGrates photo-thermal refractive (PTR) glass is an enabling technology. This work has been grounded on coupled-mode theory and numerical simulations, all with parameters consistent with PTR glass. We discuss the strengths (high efficiencies, robustness to environment) and limitations (scalability, crosstalk) of this technology. While not scalable, the utility and robustness of such optical elements for broader quantum information processing applications can be substantial.

  19. Flux-gate magnetometer for Mars exploration

    NASA Astrophysics Data System (ADS)

    Zhao, Hua; Zhu, G. W.; Yu, P.; Wang, J. D.; Yu, M. F.; Li, L.; Sun, Y. Q.; Chen, S. W.; Liao, H. Z.; Zhou, B.; Feng, Y. Y.

    2008-10-01

    A micro-satellite, Yinghuo-1, would be launched with Russian spacecraft, Phobos-Grunt in October, 2009 to investigate the space environment around Mars. YH-1 and Phobos-Grunt forms a two-point measurement configuration in the Martian space environment. YH-1 and Phobos-Grunt are equipped with similar magnetic field and plasma detecting payload on two spacecraft would give some coordinated exploration around Mars. YH-1 would orbit Mars with periapsis of 800 km above the Martian surface, and apoapsis about 80000km to the center of Mars. The orbit inclination is in the range of 0~7° to the Martian equator. A flux-gate type magnetometer, with two tri-axial sensors, is developed for YH-1 spacecraft. Two sensors are mounted on one-side of the deployable solar panel with a radial separation about 45cm to function as a gradiometer to minimize the affects of platform remanence. The dynamic range of the magnetometer is +/-256nT with a 16-bit ADC converter, and the noise level is better than 0.01nT/√Hz, to measure three-component magnetic field from DC to 10Hz. Flux-gate magnetometer would work together with the Plasma Package onboard of YH-1 to investigate the Martian bow shock, magnetosheath, magnetic pileup region (MPR). A detail description of the flux-gate magnetometer is presented in this paper, with test and calibration results.

  20. Engineering integrated photonics for heralded quantum gates

    NASA Astrophysics Data System (ADS)

    Meany, Thomas; Biggerstaff, Devon N.; Broome, Matthew A.; Fedrizzi, Alessandro; Delanty, Michael; Steel, M. J.; Gilchrist, Alexei; Marshall, Graham D.; White, Andrew G.; Withford, Michael J.

    2016-06-01

    Scaling up linear-optics quantum computing will require multi-photon gates which are compact, phase-stable, exhibit excellent quantum interference, and have success heralded by the detection of ancillary photons. We investigate the design, fabrication and characterisation of the optimal known gate scheme which meets these requirements: the Knill controlled-Z gate, implemented in integrated laser-written waveguide arrays. We show device performance to be less sensitive to phase variations in the circuit than to small deviations in the coupler reflectivity, which are expected given the tolerance values of the fabrication method. The mode fidelity is also shown to be less sensitive to reflectivity and phase errors than the process fidelity. Our best device achieves a fidelity of 0.931 ± 0.001 with the ideal 4 × 4 unitary circuit and a process fidelity of 0.680 ± 0.005 with the ideal computational-basis process.

  1. Gate manipulation of DNA capture into nanopores.

    PubMed

    He, Yuhui; Tsutsui, Makusu; Fan, Chun; Taniguchi, Masateru; Kawai, Tomoji

    2011-10-25

    Understanding biophysics governing DNA capture into a nanopore and establishing a manipulation system for the capture process are essential for nanopore-based genome sequencing. In this work, the functionality of extended electric field and electroosmotic flow (EOF) during the capture stage and their dependence on gate voltage, U(G), are investigated. We demonstrate that while both the electric field and EOF within a cis chamber make long-distance contributions to DNA capture around the pore mouth, the former effect is always capturing, while the latter causes trapping or blocking of the molecule depending on the magnitude of the gate voltage, U(G): an anionic EOF induced by high U(G) is capable of doubling the DNA trapping speed and thus the absorption radius in the cis chamber, whereas a cationic EOF by low U(G) would substantially offset the trapping effort by the electric field and even totally block DNA entrance into the pore. Based on the analysis, a gate regulation is proposed with the objective of achieving a high DNA capture rate while maintaining a low error rate.

  2. Gated Luminescence Imaging of Silicon Nanoparticles

    PubMed Central

    Joo, Jinmyoung; Liu, Xiangyou; Kotamraju, Venkata Ramana; Ruoslahti, Erkki; Nam, Yoonkey; Sailor, Michael J.

    2016-01-01

    The luminescence lifetime of nanocrystalline silicon is typically on the order of microseconds, significantly longer than the nanosecond lifetimes exhibited by fluorescent molecules naturally present in cells and tissues. Time-gated imaging, where the image is acquired at a time after termination of an excitation pulse, allows discrimination of a silicon nanoparticle probe from these endogenous signals. Because of the microsecond time scale for silicon emission, time-gated imaging is relatively simple to implement for this biocompatible and nontoxic probe. Here a time-gated system with ~10 ns resolution is described, using an intensified CCD camera and pulsed LED or laser excitation sources. The method is demonstrated by tracking the fate of mesoporous silicon nanoparticles containing the tumor-targeting peptide iRGD, administered by retro-orbital injection into live mice. Imaging of such systemically administered nanoparticles in vivo is particularly challenging because of the low concentration of probe in the targeted tissues and relatively high background signals from tissue autofluorescence. Contrast improvements of >100-fold (relative to steady-state imaging) is demonstrated in the targeted tissues. PMID:26034817

  3. Transport quantum logic gates for trapped ions

    SciTech Connect

    Leibfried, D.; Knill, E.; Ospelkaus, C.; Wineland, D. J.

    2007-09-15

    Many efforts are currently underway to build a device capable of large scale quantum information processing (QIP). Whereas QIP has been demonstrated for a few qubits in several systems, many technical difficulties must be overcome in order to construct a large-scale device. In one proposal for large-scale QIP, trapped ions are manipulated by precisely controlled light pulses and moved through and stored in multizone trap arrays. The technical overhead necessary to precisely control both the ion geometrical configurations and the laser interactions is demanding. Here we propose methods that significantly reduce the overhead on laser-beam control for performing single- and multiple-qubit operations on trapped ions. We show how a universal set of operations can be implemented by controlled transport of ions through stationary laser beams. At the same time, each laser beam can be used to perform many operations in parallel, potentially reducing the total laser power necessary to carry out QIP tasks. The overall setup necessary for implementing transport gates is simpler than for gates executed on stationary ions. We also suggest a transport-based two-qubit gate scheme utilizing microfabricated permanent magnets that can be executed without laser light.

  4. Gated Luminescence Imaging of Silicon Nanoparticles.

    PubMed

    Joo, Jinmyoung; Liu, Xiangyou; Kotamraju, Venkata Ramana; Ruoslahti, Erkki; Nam, Yoonkey; Sailor, Michael J

    2015-06-23

    The luminescence lifetime of nanocrystalline silicon is typically on the order of microseconds, significantly longer than the nanosecond lifetimes exhibited by fluorescent molecules naturally present in cells and tissues. Time-gated imaging, where the image is acquired at a time after termination of an excitation pulse, allows discrimination of a silicon nanoparticle probe from these endogenous signals. Because of the microsecond time scale for silicon emission, time-gated imaging is relatively simple to implement for this biocompatible and nontoxic probe. Here a time-gated system with ∼10 ns resolution is described, using an intensified CCD camera and pulsed LED or laser excitation sources. The method is demonstrated by tracking the fate of mesoporous silicon nanoparticles containing the tumor-targeting peptide iRGD, administered by retro-orbital injection into live mice. Imaging of such systemically administered nanoparticles in vivo is particularly challenging because of the low concentration of probe in the targeted tissues and relatively high background signals from tissue autofluorescence. Contrast improvements of >100-fold (relative to steady-state imaging) is demonstrated in the targeted tissues.

  5. Voltage-gated proton channels: what' next?

    PubMed Central

    DeCoursey, Thomas E

    2008-01-01

    This review is an attempt to identify and place in context some of the many questions about voltage-gated proton channels that remain unsolved. As the gene was identified only 2 years ago, the situation is very different than in fields where the gene has been known for decades. For the proton channel, most of the obvious and less obvious structure–function questions are still wide open. Remarkably, the proton channel protein strongly resembles the voltage-sensing domain of many voltage-gated ion channels, and thus offers a novel approach to study gating mechanisms. Another surprise is that the proton channel appears to function as a dimer, with two separate conduction pathways. A number of significant biological questions remain in dispute, unanswered, or in some cases, not yet asked. This latter deficit is ascribable to the intrinsic difficulty in evaluating the importance of one component in a complex system, and in addition, to the lack, until recently, of a means of performing an unambiguous lesion experiment, that is, of selectively eliminating the molecule in question. We still lack a potent, selective pharmacological inhibitor, but the identification of the gene has allowed the development of powerful new tools including proton channel antibodies, siRNA and knockout mice. PMID:18801839

  6. Gated Silica Mesoporous Materials in Sensing Applications

    PubMed Central

    Sancenón, Félix; Pascual, Lluís; Oroval, Mar; Aznar, Elena; Martínez-Máñez, Ramón

    2015-01-01

    Silica mesoporous supports (SMSs) have a large specific surface area and volume and are particularly exciting vehicles for delivery applications. Such container-like structures can be loaded with numerous different chemical substances, such as drugs and reporters. Gated systems also contain addressable functions at openings of voids, and cargo delivery can be controlled on-command using chemical, biochemical or physical stimuli. Many of these gated SMSs have been applied for drug delivery. However, fewer examples of their use in sensing protocols have been reported. The approach of applying SMSs in sensing uses another concept—that of loading pores with a reporter and designing a capping mechanism that is selectively opened in the presence of a target analyte, which results in the delivery of the reporter. According to this concept, we provide herein a complete compilation of published examples of probes based on the use of capped SMSs for sensing. Examples for the detection of anions, cations, small molecules and biomolecules are provided. The diverse range of gated silica mesoporous materials presented here highlights their usefulness in recognition protocols. PMID:26491626

  7. Engineering integrated photonics for heralded quantum gates

    PubMed Central

    Meany, Thomas; Biggerstaff, Devon N.; Broome, Matthew A.; Fedrizzi, Alessandro; Delanty, Michael; Steel, M. J.; Gilchrist, Alexei; Marshall, Graham D.; White, Andrew G.; Withford, Michael J.

    2016-01-01

    Scaling up linear-optics quantum computing will require multi-photon gates which are compact, phase-stable, exhibit excellent quantum interference, and have success heralded by the detection of ancillary photons. We investigate the design, fabrication and characterisation of the optimal known gate scheme which meets these requirements: the Knill controlled-Z gate, implemented in integrated laser-written waveguide arrays. We show device performance to be less sensitive to phase variations in the circuit than to small deviations in the coupler reflectivity, which are expected given the tolerance values of the fabrication method. The mode fidelity is also shown to be less sensitive to reflectivity and phase errors than the process fidelity. Our best device achieves a fidelity of 0.931 ± 0.001 with the ideal 4 × 4 unitary circuit and a process fidelity of 0.680 ± 0.005 with the ideal computational-basis process. PMID:27282928

  8. Gated Irradiation With Scanned Particle Beams

    SciTech Connect

    Bert, Christoph Gemmel, Alexander; Saito, Nami; Rietzel, Eike

    2009-03-15

    Purpose: To demonstrate mitigation of the interplay effects of scanned particle beams and residual target motion within a gating window by increased overlap of pencil beams. Methods and Materials: Lateral overlap was increased by increasing the pencil beam widths or by decreasing the distance between the pencil beams (scan grid). Longitudinal overlap was increased by reducing the distance between iso-range slices. For scanned carbon ion beams, simulation studies were performed and validated experimentally to determine the required parameters for different residual motion characteristics. The dose distributions were characterized by the maximal local deviations representing local over- and underdosage. Results: For residual lateral motion, the local deviations were <5% for 2, 4, and 7 mm residual motion within the gating window for a 2-mm scan grid and pencil beams of 10, 14, and 18 mm full width at half maximum, respectively. Decreasing the iso-range slice distance from 3 mm to 1 mm effectively mitigated {<=}10 mm water-equivalent range changes. Experimental data reproduced the simulation results. Conclusion: In charged particle therapy with a scanned beam, interplay effects between gated beam delivery and residual target motion can be decreased effectively by increasing the overlap between pencil beams laterally, as well as longitudinally.

  9. Engineering integrated photonics for heralded quantum gates.

    PubMed

    Meany, Thomas; Biggerstaff, Devon N; Broome, Matthew A; Fedrizzi, Alessandro; Delanty, Michael; Steel, M J; Gilchrist, Alexei; Marshall, Graham D; White, Andrew G; Withford, Michael J

    2016-06-10

    Scaling up linear-optics quantum computing will require multi-photon gates which are compact, phase-stable, exhibit excellent quantum interference, and have success heralded by the detection of ancillary photons. We investigate the design, fabrication and characterisation of the optimal known gate scheme which meets these requirements: the Knill controlled-Z gate, implemented in integrated laser-written waveguide arrays. We show device performance to be less sensitive to phase variations in the circuit than to small deviations in the coupler reflectivity, which are expected given the tolerance values of the fabrication method. The mode fidelity is also shown to be less sensitive to reflectivity and phase errors than the process fidelity. Our best device achieves a fidelity of 0.931 ± 0.001 with the ideal 4 × 4 unitary circuit and a process fidelity of 0.680 ± 0.005 with the ideal computational-basis process.

  10. Gate-Tunable Conducting Oxide Metasurfaces.

    PubMed

    Huang, Yao-Wei; Lee, Ho Wai Howard; Sokhoyan, Ruzan; Pala, Ragip A; Thyagarajan, Krishnan; Han, Seunghoon; Tsai, Din Ping; Atwater, Harry A

    2016-09-14

    Metasurfaces composed of planar arrays of subwavelength artificial structures show promise for extraordinary light manipulation. They have yielded novel ultrathin optical components such as flat lenses, wave plates, holographic surfaces, and orbital angular momentum manipulation and detection over a broad range of the electromagnetic spectrum. However, the optical properties of metasurfaces developed to date do not allow for versatile tunability of reflected or transmitted wave amplitude and phase after their fabrication, thus limiting their use in a wide range of applications. Here, we experimentally demonstrate a gate-tunable metasurface that enables dynamic electrical control of the phase and amplitude of the plane wave reflected from the metasurface. Tunability arises from field-effect modulation of the complex refractive index of conducting oxide layers incorporated into metasurface antenna elements which are configured in reflectarray geometry. We measure a phase shift of 180° and ∼30% change in the reflectance by applying 2.5 V gate bias. Additionally, we demonstrate modulation at frequencies exceeding 10 MHz and electrical switching of ±1 order diffracted beams by electrical control over subgroups of metasurface elements, a basic requirement for electrically tunable beam-steering phased array metasurfaces. In principle, electrically gated phase and amplitude control allows for electrical addressability of individual metasurface elements and opens the path to applications in ultrathin optical components for imaging and sensing technologies, such as reconfigurable beam steering devices, dynamic holograms, tunable ultrathin lenses, nanoprojectors, and nanoscale spatial light modulators.

  11. Quantum superreplication of states and gates

    NASA Astrophysics Data System (ADS)

    Chiribella, Giulio; Yang, Yuxiang

    2016-06-01

    Although the no-cloning theorem forbids perfect replication of quantum information, it is sometimes possible to produce large numbers of replicas with vanishingly small error. This phenomenon, known as quantum superreplication, can occur for both quantum states and quantum gates. The aim of this paper is to review the central features of quantum superreplication and provide a unified view of existing results. The paper also includes new results. In particular, we show that when quantum superreplication can be achieved, it can be achieved through estimation up to an error of size O( M/ N 2), where N and M are the number of input and output copies, respectively. Quantum strategies still offer an advantage for superreplication in that they allow for exponentially faster reduction of the error. Using the relation with estimation, we provide i) an alternative proof of the optimality of Heisenberg scaling in quantum metrology, ii) a strategy for estimating arbitrary unitary gates with a mean square error scaling as log N/ N 2, and iii) a protocol that generates O( N 2) nearly perfect copies of a generic pure state U |0> while using the corresponding gate U only N times. Finally, we point out that superreplication can be achieved using interactions among k systems, provided that k is large compared to M 2/ N 2.

  12. Optical control of an ion channel gate

    PubMed Central

    Lemoine, Damien; Habermacher, Chloé; Martz, Adeline; Méry, Pierre-François; Bouquier, Nathalie; Diverchy, Fanny; Taly, Antoine; Rassendren, François; Specht, Alexandre; Grutter, Thomas

    2013-01-01

    The powerful optogenetic pharmacology method allows the optical control of neuronal activity by photoswitchable ligands tethered to channels and receptors. However, this approach is technically demanding, as it requires the design of pharmacologically active ligands. The development of versatile technologies therefore represents a challenging issue. Here, we present optogating, a method in which the gating machinery of an ATP-activated P2X channel was reprogrammed to respond to light. We found that channels covalently modified by azobenzene-containing reagents at the transmembrane segments could be reversibly turned on and off by light, without the need of ATP, thus revealing an agonist-independent, light-induced gating mechanism. We demonstrate photocontrol of neuronal activity by a light-gated, ATP-insensitive P2X receptor, providing an original tool devoid of endogenous sensitivity to delineate P2X signaling in normal and pathological states. These findings open new avenues to specifically activate other ion channels independently of their natural stimulus. PMID:24297890

  13. Gating the glutamate gate of CLC-2 chloride channel by pore occupancy.

    PubMed

    De Jesús-Pérez, José J; Castro-Chong, Alejandra; Shieh, Ru-Chi; Hernández-Carballo, Carmen Y; De Santiago-Castillo, José A; Arreola, Jorge

    2016-01-01

    CLC-2 channels are dimeric double-barreled chloride channels that open in response to hyperpolarization. Hyperpolarization activates protopore gates that independently regulate the permeability of the pore in each subunit and the common gate that affects the permeability through both pores. CLC-2 channels lack classic transmembrane voltage-sensing domains; instead, their protopore gates (residing within the pore and each formed by the side chain of a glutamate residue) open under repulsion by permeant intracellular anions or protonation by extracellular H(+). Here, we show that voltage-dependent gating of CLC-2: (a) is facilitated when permeant anions (Cl(-), Br(-), SCN(-), and I(-)) are present in the cytosolic side; (b) happens with poorly permeant anions fluoride, glutamate, gluconate, and methanesulfonate present in the cytosolic side; (c) depends on pore occupancy by permeant and poorly permeant anions; (d) is strongly facilitated by multi-ion occupancy; (e) is absent under likely protonation conditions (pHe = 5.5 or 6.5) in cells dialyzed with acetate (an impermeant anion); and (f) was the same at intracellular pH 7.3 and 4.2; and (g) is observed in both whole-cell and inside-out patches exposed to increasing [Cl(-)]i under unlikely protonation conditions (pHe = 10). Thus, based on our results we propose that hyperpolarization activates CLC-2 mainly by driving intracellular anions into the channel pores, and that protonation by extracellular H(+) plays a minor role in dislodging the glutamate gate.

  14. Optimizing Controlling-Value-Based Power Gating with Gate Count and Switching Activity

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Kimura, Shinji

    In this paper, a new heuristic algorithm is proposed to optimize the power domain clustering in controlling-value-based (CV-based) power gating technology. In this algorithm, both the switching activity of sleep signals (p) and the overall numbers of sleep gates (gate count, N) are considered, and the sum of the product of p and N is optimized. The algorithm effectively exerts the total power reduction obtained from the CV-based power gating. Even when the maximum depth is kept to be the same, the proposed algorithm can still achieve power reduction approximately 10% more than that of the prior algorithms. Furthermore, detailed comparison between the proposed heuristic algorithm and other possible heuristic algorithms are also presented. HSPICE simulation results show that over 26% of total power reduction can be obtained by using the new heuristic algorithm. In addition, the effect of dynamic power reduction through the CV-based power gating method and the delay overhead caused by the switching of sleep transistors are also shown in this paper.

  15. Hetero-gate-Dielectric Symmetric U-shaped gate tunnel FET

    NASA Astrophysics Data System (ADS)

    Tajally, Mohammad Bagher; Karami, Mohammad Azim

    2017-10-01

    Heterogeneous gate dielectric is used in a nanoscale symmetric U-shaped gate tunnel FET (SUTFET), which resulted in ION, IOFF, subthreshold swing (SS), and Iambipolar enhancement. ION of 1.5 × 10-5 A/μm, IOFF of 6 × 10-12 A/μm, average subthreshold swing of (SS) 19.83 mV/decade from 0 V < VGS < VThreshold, and Iambipolar of 5 × 10-9 A/μm are obtained by using high-k dielectric close to the source and low-k dielectric in the vicinity of drain. The gate dielectric engineering shows characteristic enhancement in compare to SUTFET with single gate dielectric material. The strong coupling between the gate and transistor channel near the source results in reduced potential barrier width in tunnel junction, which leads to higher ION and lower subthreshold swing. Moreover, the presence of low-k dielectric near the drain reduces ambipolar current by increasing potential barrier height. This improved SUTFET characteristics makes it suitable for the usage in digital circuits due to reduced ambipolar response.

  16. Charge movement in gating-locked HCN channels reveals weak coupling of voltage sensors and gate.

    PubMed

    Ryu, Sujung; Yellen, Gary

    2012-11-01

    HCN (hyperpolarization-activated cyclic nucleotide gated) pacemaker channels have an architecture similar to that of voltage-gated K(+) channels, but they open with the opposite voltage dependence. HCN channels use essentially the same positively charged voltage sensors and intracellular activation gates as K(+) channels, but apparently these two components are coupled differently. In this study, we examine the energetics of coupling between the voltage sensor and the pore by using cysteine mutant channels for which low concentrations of Cd(2+) ions freeze the open-closed gating machinery but still allow the sensors to move. We were able to lock mutant channels either into open or into closed states by the application of Cd(2+) and measure the effect on voltage sensor movement. Cd(2+) did not immobilize the gating charge, as expected for strict coupling, but rather it produced shifts in the voltage dependence of voltage sensor charge movement, consistent with its effect of confining transitions to either closed or open states. From the magnitude of the Cd(2+)-induced shifts, we estimate that each voltage sensor produces a roughly three- to sevenfold effect on the open-closed equilibrium, corresponding to a coupling energy of ∼1.3-2 kT per sensor. Such coupling is not only opposite in sign to the coupling in K(+) channels, but also much weaker.

  17. Gating the glutamate gate of CLC-2 chloride channel by pore occupancy

    PubMed Central

    De Jesús-Pérez, José J.; Castro-Chong, Alejandra; Shieh, Ru-Chi; Hernández-Carballo, Carmen Y.; De Santiago-Castillo, José A.

    2016-01-01

    CLC-2 channels are dimeric double-barreled chloride channels that open in response to hyperpolarization. Hyperpolarization activates protopore gates that independently regulate the permeability of the pore in each subunit and the common gate that affects the permeability through both pores. CLC-2 channels lack classic transmembrane voltage–sensing domains; instead, their protopore gates (residing within the pore and each formed by the side chain of a glutamate residue) open under repulsion by permeant intracellular anions or protonation by extracellular H+. Here, we show that voltage-dependent gating of CLC-2: (a) is facilitated when permeant anions (Cl−, Br−, SCN−, and I−) are present in the cytosolic side; (b) happens with poorly permeant anions fluoride, glutamate, gluconate, and methanesulfonate present in the cytosolic side; (c) depends on pore occupancy by permeant and poorly permeant anions; (d) is strongly facilitated by multi-ion occupancy; (e) is absent under likely protonation conditions (pHe = 5.5 or 6.5) in cells dialyzed with acetate (an impermeant anion); and (f) was the same at intracellular pH 7.3 and 4.2; and (g) is observed in both whole-cell and inside-out patches exposed to increasing [Cl−]i under unlikely protonation conditions (pHe = 10). Thus, based on our results we propose that hyperpolarization activates CLC-2 mainly by driving intracellular anions into the channel pores, and that protonation by extracellular H+ plays a minor role in dislodging the glutamate gate. PMID:26666914

  18. The cooperative voltage sensor motion that gates a potassium channel.

    PubMed

    Pathak, Medha; Kurtz, Lisa; Tombola, Francesco; Isacoff, Ehud

    2005-01-01

    The four arginine-rich S4 helices of a voltage-gated channel move outward through the membrane in response to depolarization, opening and closing gates to generate a transient ionic current. Coupling of voltage sensing to gating was originally thought to operate with the S4s moving independently from an inward/resting to an outward/activated conformation, so that when all four S4s are activated, the gates are driven to open or closed. However, S4 has also been found to influence the cooperative opening step (Smith-Maxwell et al., 1998a), suggesting a more complex mechanism of coupling. Using fluorescence to monitor structural rearrangements in a Shaker channel mutant, the ILT channel (Ledwell and Aldrich, 1999), that energetically isolates the steps of activation from the cooperative opening step, we find that opening is accompanied by a previously unknown and cooperative movement of S4. This gating motion of S4 appears to be coupled to the internal S6 gate and to two forms of slow inactivation. Our results suggest that S4 plays a direct role in gating. While large transmembrane rearrangements of S4 may be required to unlock the gating machinery, as proposed before, it appears to be the gating motion of S4 that drives the gates to open and close.

  19. Analysis of gate underlap channel double gate MOS transistor for electrical detection of bio-molecules

    NASA Astrophysics Data System (ADS)

    Ajay; Narang, Rakhi; Saxena, Manoj; Gupta, Mridula

    2015-12-01

    In this paper, an analytical model for gate drain underlap channel Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistor (DG-MOSFET) for label free electrical detection of biomolecules has been proposed. The conformal mapping technique has been used to derive the expressions for surface potential, lateral electric field, energy bands (i.e. conduction and valence band) and threshold voltage (Vth). Subsequently a full drain current model to analyze the sensitivity of the biosensor has been developed. The shift in the threshold voltage and drain current (after the biomolecules interaction with the gate underlap channel region of the MOS transistor) has been used as a sensing metric. All the characteristic trends have been verified through ATLAS (SILVACO) device simulation results.

  20. Gate tunneling current and quantum capacitance in metal-oxide-semiconductor devices with graphene gate electrodes

    NASA Astrophysics Data System (ADS)

    An, Yanbin; Shekhawat, Aniruddh; Behnam, Ashkan; Pop, Eric; Ural, Ant

    2016-11-01

    Metal-oxide-semiconductor (MOS) devices with graphene as the metal gate electrode, silicon dioxide with thicknesses ranging from 5 to 20 nm as the dielectric, and p-type silicon as the semiconductor are fabricated and characterized. It is found that Fowler-Nordheim (F-N) tunneling dominates the gate tunneling current in these devices for oxide thicknesses of 10 nm and larger, whereas for devices with 5 nm oxide, direct tunneling starts to play a role in determining the total gate current. Furthermore, the temperature dependences of the F-N tunneling current for the 10 nm devices are characterized in the temperature range 77-300 K. The F-N coefficients and the effective tunneling barrier height are extracted as a function of temperature. It is found that the effective barrier height decreases with increasing temperature, which is in agreement with the results previously reported for conventional MOS devices with polysilicon or metal gate electrodes. In addition, high frequency capacitance-voltage measurements of these MOS devices are performed, which depict a local capacitance minimum under accumulation for thin oxides. By analyzing the data using numerical calculations based on the modified density of states of graphene in the presence of charged impurities, it is shown that this local minimum is due to the contribution of the quantum capacitance of graphene. Finally, the workfunction of the graphene gate electrode is extracted by determining the flat-band voltage as a function of oxide thickness. These results show that graphene is a promising candidate as the gate electrode in metal-oxide-semiconductor devices.

  1. Inversion gate capacitance of undoped single-gate and double-gate field-effect transistor geometries in the extreme quantum limit

    SciTech Connect

    Majumdar, Amlan

    2015-05-28

    We present first-principle analytical derivations and numerically modeled data to show that the gate capacitance per unit gate area C{sub G} of extremely thin undoped-channel single-gate and double-gate field-effect transistor geometries in the extreme quantum limit with single-subband occupancy can be written as 1/C{sub G} = 1/C{sub OX} + N{sub G}/C{sub DOS} + N{sub G}/ηC{sub WF}, where N{sub G} is the number of gates, C{sub OX} is the oxide capacitance per unit area, C{sub DOS} is the density-of-states capacitance per unit area, C{sub WF} is the wave function spreading capacitance per unit area, and η is a constant on the order of 1.

  2. SU-E-T-350: Verification of Gating Performance of a New Elekta Gating Solution: Response Kit and Catalyst System

    SciTech Connect

    Xie, X; Cao, D; Housley, D; Mehta, V; Shepard, D

    2014-06-01

    Purpose: In this work, we have tested the performance of new respiratory gating solutions for Elekta linacs. These solutions include the Response gating and the C-RAD Catalyst surface mapping system.Verification measurements have been performed for a series of clinical cases. We also examined the beam on latency of the system and its impact on delivery efficiency. Methods: To verify the benefits of tighter gating windows, a Quasar Respiratory Motion Platform was used. Its vertical-motion plate acted as a respiration surrogate and was tracked by the Catalyst system to generate gating signals. A MatriXX ion-chamber array was mounted on its longitudinal-moving platform. Clinical plans are delivered to a stationary and moving Matrix array at 100%, 50% and 30% gating windows and gamma scores were calculated comparing moving delivery results to the stationary result. It is important to note that as one moves to tighter gating windows, the delivery efficiency will be impacted by the linac's beam-on latency. Using a specialized software package, we generated beam-on signals of lengths of 1000ms, 600ms, 450ms, 400ms, 350ms and 300ms. As the gating windows get tighter, one can expect to reach a point where the dose rate will fall to nearly zero, indicating that the gating window is close to beam-on latency. A clinically useful gating window needs to be significantly longer than the latency for the linac. Results: As expected, the use of tighter gating windows improved delivery accuracy. However, a lower limit of the gating window, largely defined by linac beam-on latency, exists at around 300ms. Conclusion: The Response gating kit, combined with the C-RAD Catalyst, provides an effective solution for respiratorygated treatment delivery. Careful patient selection, gating window design, even visual/audio coaching may be necessary to ensure both delivery quality and efficiency. This research project is funded by Elekta.

  3. Efficient measurement of quantum gate error by interleaved randomized benchmarking.

    PubMed

    Magesan, Easwar; Gambetta, Jay M; Johnson, B R; Ryan, Colm A; Chow, Jerry M; Merkel, Seth T; da Silva, Marcus P; Keefe, George A; Rothwell, Mary B; Ohki, Thomas A; Ketchen, Mark B; Steffen, M

    2012-08-24

    We describe a scalable experimental protocol for estimating the average error of individual quantum computational gates. This protocol consists of interleaving random Clifford gates between the gate of interest and provides an estimate as well as theoretical bounds for the average error of the gate under test, so long as the average noise variation over all Clifford gates is small. This technique takes into account both state preparation and measurement errors and is scalable in the number of qubits. We apply this protocol to a superconducting qubit system and find a bounded average error of 0.003 [0,0.016] for the single-qubit gates X(π/2) and Y(π/2). These bounded values provide better estimates of the average error than those extracted via quantum process tomography.

  4. Electric nonadiabatic geometric entangling gates on spin qubits

    NASA Astrophysics Data System (ADS)

    Azimi Mousolou, Vahid

    2017-07-01

    Producing and maintaining entanglement reside at the heart of the optimal construction of quantum operations and are fundamental issues in the realization of universal quantum computation. We here introduce a setup of spin qubits that allows the geometric implementation of entangling gates between the register qubits with any arbitrary entangling power. We show this by demonstrating a circuit through a spin chain, which performs universal nonadiabatic holonomic two-qubit entanglers. The proposed gates are all electric and geometric, which would help to realize fast and robust entangling gates on spin qubits. This family of entangling gates contains gates that are as efficient as the cnot gate in quantum algorithms. We examine the robustness of the circuit to some extent.

  5. Investigation of field induced trapping on floating gates

    NASA Technical Reports Server (NTRS)

    Gosney, W. M.

    1975-01-01

    The development of a technology for building electrically alterable read only memories (EAROMs) or reprogrammable read only memories (RPROMs) using a single level metal gate p channel MOS process with all conventional processing steps is outlined. Nonvolatile storage of data is achieved by the use of charged floating gate electrodes. The floating gates are charged by avalanche injection of hot electrodes through gate oxide, and discharged by avalanche injection of hot holes through gate oxide. Three extra diffusion and patterning steps are all that is required to convert a standard p channel MOS process into a nonvolatile memory process. For identification, this nonvolatile memory technology was given the descriptive acronym DIFMOS which stands for Dual Injector, Floating gate MOS.

  6. Electrochemical Single-Molecule Transistors with Optimized Gate Coupling.

    PubMed

    Osorio, Henrry M; Catarelli, Samantha; Cea, Pilar; Gluyas, Josef B G; Hartl, František; Higgins, Simon J; Leary, Edmund; Low, Paul J; Martín, Santiago; Nichols, Richard J; Tory, Joanne; Ulstrup, Jens; Vezzoli, Andrea; Milan, David C; Zeng, Qiang

    2015-11-18

    Electrochemical gating at the single molecule level of viologen molecular bridges in ionic liquids is examined. Contrary to previous data recorded in aqueous electrolytes, a clear and sharp peak in the single molecule conductance versus electrochemical potential data is obtained in ionic liquids. These data are rationalized in terms of a two-step electrochemical model for charge transport across the redox bridge. In this model the gate coupling in the ionic liquid is found to be fully effective with a modeled gate coupling parameter, ξ, of unity. This compares to a much lower gate coupling parameter of 0.2 for the equivalent aqueous gating system. This study shows that ionic liquids are far more effective media for gating the conductance of single molecules than either solid-state three-terminal platforms created using nanolithography, or aqueous media.

  7. Shorter gate sequences for quantum computing by mixing unitaries

    NASA Astrophysics Data System (ADS)

    Campbell, Earl

    2017-04-01

    Fault-tolerant quantum computers compose elements of a discrete gate set in order to approximate a target unitary. The problem of minimizing the number of gates is known as gate synthesis. The approximation error is a form of coherent noise, which can be significantly more damaging than comparable incoherent noise. We show how mixing over different gate sequences can convert this coherent noise into an incoherent form. As measured by diamond distance, the postmixing noise is quadratically smaller than before mixing, without increasing resource cost upper bounds. Equivalently, we can look for shorter gate sequences that achieve the same precision as unitary gate synthesis. For a broad class of problems this gives a factor 1 /2 reduction in worst-case resource costs.

  8. Reconfigurable and non-volatile vertical magnetic logic gates

    SciTech Connect

    Butler, J. Lee, B.; Shachar, M.; Garcia, D.; Hu, B.; Hong, J.; Amos, N.; Khizroev, S.

    2014-04-28

    In this paper, we discuss the concept and prototype fabrication of reconfigurable and non-volatile vertical magnetic logic gates. These gates consist of two input layers and a RESET layer. The RESET layer allows the structure to be used as either an AND or an OR gate, depending on its magnetization state. To prove this concept, the gates were fabricated using a multi-layered patterned magnetic media, in which three magnetic layers are stacked and exchange-decoupled via non-magnetic interlayers. We demonstrate the functionality of these logic gates by conducting atomic force microscopy and magnetic force microscopy (MFM) analysis of the multi-layered patterned magnetic media. The logic gates operation mechanism and fabrication feasibility are both validated by the MFM imaging results.

  9. Gate-Level Commercial Microelectronics Verification with Standard Cell Recognition

    DTIC Science & Technology

    2015-03-26

    GATE- LEVEL COMMERCIAL MICROELECTRONICS VERIFICATION WITH STANDARD CELL RECOGNITION THESIS Leleia A. Hsia, Second Lieutenant, USAF AFIT-ENG-MS-15-M...Government and is not subject to copyright protection in the United States. AFIT-ENG-MS-15-M-069 GATE- LEVEL COMMERCIAL MICROELECTRONICS VERIFICATION WITH...RELEASE; DISTRIBUTION UNLIMITED AFIT-ENG-MS-15-M-069 GATE- LEVEL COMMERCIAL MICROELECTRONICS VERIFICATION WITH STANDARD CELL RECOGNITION THESIS Leleia A

  10. The Latest Information on Fort Detrick Gate Access Procedures | Poster

    Cancer.gov

    As of Jan. 5, all visitors to Fort Detrick are required to undergo a National Crime Information Center background check prior to entering base. The background checks are conducted at Old Farm Gate. The new access procedures may cause delays at all Fort Detrick gates, but especially at Old Farm Gate. Access requirements have not changed for employees and personnel with a federal/NIH PIV card. Other types of identification badges are no longer acceptable.

  11. STIR: Novel Electronic States by Gating Strongly Correlated Materials

    DTIC Science & Technology

    2016-03-01

    plan built on my group’s recent demonstration of electrolyte gating in Strontium Titanate, using an atomically thin hexagonal Boron Nitride barrier to...demonstration of electrolyte gating in Strontium Titanate, using an atomically thin hexagonal Boron Nitride barrier to prevent disorder and chemical...recent demonstration of electrolyte gating in Strontium Titanate, using an atomically thin hexagonal Boron Nitride barrier to prevent disorder and

  12. 100. Photocopied August 1978. COMPENSATING GATES, VIEW LOOKING SOUTHWEST, JULY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    100. Photocopied August 1978. COMPENSATING GATES, VIEW LOOKING SOUTHWEST, JULY 8, 1916. COMPLETED GATES 13-16 ARE AT THE LEFT. THE PIERS OF GATES 9-12 ARE ON THE RIGHT. SUPER-STRUCTURE ERECTION ON THESE PIERS HAD NOT YET BEGUN. JUST ABOVE THE COFFER DAM, THE BREAKWATER INSTALLED TO PROTECT THE CONSTRUCTION SITE FROM THE RIVER CURRENT CAN BE SEEN. (684) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  13. Non-rigid summing of gated PET via optical flow

    SciTech Connect

    Klein, G.J.; Reutter, B.W.; Huesman, R.H. |

    1996-12-31

    A method for summing together datasets from gated cardiac PET acquisitions is described. Optical flow techniques are used to accurately model non-rigid motion present during the cardiac cycle so that a one-to-one mapping is found between each voxel of two gated volumes. Using this mapping, image summing can take place, producing a composite dataset with improved statistics and reduced motion-induced blur. Results using a data from a gated cardiac study on a dog are presented.

  14. The Latest Information on Fort Detrick Gate Access Procedures | Poster

    Cancer.gov

    As of Jan. 5, all visitors to Fort Detrick are required to undergo a National Crime Information Center background check prior to entering base. The background checks are conducted at Old Farm Gate. The new access procedures may cause delays at all Fort Detrick gates, but especially at Old Farm Gate. Access requirements have not changed for employees and personnel with a federal/NIH PIV card. Other types of identification badges are no longer acceptable.

  15. Biophysics, pathophysiology, and pharmacology of ion channel gating pores

    PubMed Central

    Moreau, Adrien; Gosselin-Badaroudine, Pascal; Chahine, Mohamed

    2014-01-01

    Voltage sensor domains (VSDs) are a feature of voltage gated ion channels (VGICs) and voltage sensitive proteins. They are composed of four transmembrane (TM) segments (S1–S4). Currents leaking through VSDs are called omega or gating pore currents. Gating pores are caused by mutations of the highly conserved positively charged amino acids in the S4 segment that disrupt interactions between the S4 segment and the gating charge transfer center (GCTC). The GCTC separates the intracellular and extracellular water crevices. The disruption of S4–GCTC interactions allows these crevices to communicate and create a fast activating and non-inactivating alternative cation-selective permeation pathway of low conductance, or a gating pore. Gating pore currents have recently been shown to cause periodic paralysis phenotypes. There is also increasing evidence that gating pores are linked to several other familial diseases. For example, gating pores in Nav1.5 and Kv7.2 channels may underlie mixed arrhythmias associated with dilated cardiomyopathy (DCM) phenotypes and peripheral nerve hyperexcitability (PNH), respectively. There is little evidence for the existence of gating pore blockers. Moreover, it is known that a number of toxins bind to the VSD of a specific domain of Na+ channels. These toxins may thus modulate gating pore currents. This focus on the VSD motif opens up a new area of research centered on developing molecules to treat a number of cell excitability disorders such as epilepsy, cardiac arrhythmias, and pain. The purpose of the present review is to summarize existing knowledge of the pathophysiology, biophysics, and pharmacology of gating pore currents and to serve as a guide for future studies aimed at improving our understanding of gating pores and their pathophysiological roles. PMID:24772081

  16. Lateralization of auditory sensory gating and neuropsychological dysfunction in schizophrenia.

    PubMed

    Thoma, Robert J; Hanlon, Faith M; Moses, Sandra N; Edgar, J Christopher; Huang, Mingxiong; Weisend, Michael P; Irwin, Jessica; Sherwood, Andrea; Paulson, Kim; Bustillo, Juan; Adler, Lawrence E; Miller, Gregory A; Cañive, Jose M

    2003-09-01

    Sensory gating assessed via EEG in a paired-click paradigm has often served as a neurophysiological metric of attentional function in schizophrenia. However, the standard EEG measure of sensory gating using the P50 component at electrode Cz does not foster differential assessment of left and right hemisphere contributions. Magnetoencephalography (MEG) is complementary to EEG, and its analogous M50 component may be better suited for localization and analysis of such lateralized cortical generators. The authors hypothesized that 1) auditory gating would be evident in M50 sources in superior temporal gyrus, demonstrating ratios similar to P50; 2) M50 would resemble P50 in distinguishing gating in comparison subjects and patients with schizophrenia, but M50 would show lateralization of the gating deficit; and 3) P50 and M50 sensory gating ratios would predict neuropsychological measures in patients and comparison subjects, with the MEG identification of left and right hemisphere sources allowing for the evaluation of lateralization in brain-behavior relationships. Event-related EEG and MEG recordings were simultaneously obtained from 20 patients with schizophrenia and 15 comparison subjects. P50 amplitudes, M50 dipole source strengths, and P50 and M50 gating ratios were compared and assessed with respect to scores on neuropsychological performance measures. M50 dipoles localizing to superior temporal gyrus demonstrated gating similar to that of P50. As expected, patients demonstrated less P50 gating than did comparison subjects. Left (but not right) hemisphere M50 gating 1) correlated with EEG gating, 2) differentiated patients and comparison subjects, and 3) correlated with neuropsychological measures of sustained attention and working memory. Converging evidence from EEG, MEG, and neuropsychological measures points to left hemisphere dysfunction as strongly related to the well-established sensory gating deficit in schizophrenia.

  17. Implementation of Structures in the CMS: Part 4, Tide Gate

    DTIC Science & Technology

    2013-08-01

    salinity and sediment management (Figure 1). Because a tide gate is a significant component of hydrodynamic and sediment transport controls in the coastal... transport , and morphology change in coastal and inlet applications. It consists of a hydrodynamic and sediment transport model, CMS-Flow, and a spectral...sediment transport with tide gates, the salinity and suspended sediment will be transported over tide gate structures, but the bed load will be trapped if

  18. Optimal length of decomposition sequences composed of imperfect gates

    NASA Astrophysics Data System (ADS)

    Nam, Y. S.; Blümel, R.

    2017-05-01

    Quantum error correcting circuitry is both a resource for correcting errors and a source for generating errors. A balance has to be struck between these two aspects. Perfect quantum gates do not exist in nature. Therefore, it is important to investigate how flaws in the quantum hardware affect quantum computing performance. We do this in two steps. First, in the presence of realistic, faulty quantum hardware, we establish how quantum error correction circuitry achieves reduction in the extent of quantum information corruption. Then, we investigate fault-tolerant gate sequence techniques that result in an approximate phase rotation gate, and establish the existence of an optimal length L_{ {opt}} of the length L of the decomposition sequence. The existence of L_{ {opt}} is due to the competition between the increase in gate accuracy with increasing L, but the decrease in gate performance due to the diffusive proliferation of gate errors due to faulty basis gates. We present an analytical formula for the gate fidelity as a function of L that is in satisfactory agreement with the results of our simulations and allows the determination of L_{ {opt}} via the solution of a transcendental equation. Our result is universally applicable since gate sequence approximations also play an important role, e.g., in atomic and molecular physics and in nuclear magnetic resonance.

  19. Frequency tracked gated pulse technique for ultrasonic frequency

    NASA Technical Reports Server (NTRS)

    Cantrell, Jr., John H. (Inventor); Heyman, Joseph S. (Inventor)

    1983-01-01

    A tracking generator 21 is slaved to a spectrum analyzer 23 to produce an input signal having a frequency that follows the frequency of the spectrum analyzer sweeping local oscillator 22. The input signal is gated to a transducer 26 by a transmitter gate 25 to produce ultrasonic waves in the sample 28. The resulting ultrasonic echoes are converted into electrical signals by the transducer and then gated into the spectrum analyzer by receiver gate 29. This arrangement produces spectra that are equivalent to shock-exciting the transducer with a true delta function shock-excitation.

  20. Stacked-Gate FET's For Analog Memory Elements

    NASA Technical Reports Server (NTRS)

    Thakoor, Anilkumar P.; Moopenn, Alexander W.

    1991-01-01

    Three-terminal, double-stacked-gate field-effect transistor (FET), developed as analog memory element. Particularly suited for use as synapse with variable connection strength in electronic neural network. Provides programmable, nonvolatile resistive connection, somewhat in manner of porous-gate FET described in "Porous-Floating-Gate Field-Effect Transistor" (NPO-17532). Resembles commercial erasable programmable read-only memory (EPROM) device, except for thickness of layers of silicon dioxide electrically isolating gates. Either p-channel or n-channel device.